I decided to preach an Advent series this December, that is, an Advent sermon on each of the four Sunday mornings this December. I’ve done this several times before, most recently in 2010. But this may be my last opportunity and what preacher does not take particular pleasure in preaching sermons apropos Christmas! For my text for this first sermon, I chose one of the most famous in the Bible. Just the one verse: John 3:16. If there is any verse in the Bible that can be preached by itself, without careful attention to its context, it is John 3:16!

“For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life.”

One comment on the verse is appropriate this morning. The first century Jew had no doubt that God loved Israel, but no one has yet been able to find in the Jewish writings of the period any statement that God loved the world. It is a distinctively Christian idea [cf. Morris, NICNT, 229] that the love of God is not confined to any nationality or race or even to any religious community. Most people nowadays think that God loves everyone. What they don’t know is that only Christianity teaches both that God is love and that his love embraces the entire world!

But now to my subject this morning. It is a question of Christian theology; a much discussed question but more so in past days when theology was more important to Christians than it is today. It is the sort of question people can think is irrelevant to daily life, a matter too technical, too cerebral; but it is not so. It is the sort of question that serious Christians should think about and, if they do, will find stirring, inspiring, humbling, and soul-purifying.

I’ve entitled the sermon Cur Deus Homo. It is actually a question. It doesn’t end with a question mark because classical and medieval Latin didn’t employ punctuation. Latin had no question mark. The form of the question is not, of course, original to me. Cur Deus Homo is the title of one of the most important works of Christian theology ever written. In fact, it was once described as “the truest and greatest book on the atonement that has ever been written.” [J. Denney, Atonement, 116] “Atonement,” of course as you know, refers to Christ’s death on the cross for our sins. In English the title of Anselm of Canterbury’s 11th century book would be: Why did God become Man? In his very first chapter, Anselm explains why he wrote the book.

“…this question, both unbelievers…bring up against us…and many believers ponder it in their hearts: for what cause or necessity [did] God become man, and by his own death, as we believe and affirm, restore life to the world; when [God] might have done this by means of some other being, angelic or human, or merely by his will. Not only the learned, but also many unlearned persons are interested in this question and want to know the answer.”

In other words, why the incarnation? Why the cross? Or, in the language of John 3:16, why did God give his only son? That is clearly what “gave” means here. God gave his son to the world by sending him into the world for the salvation of his people. John has already described the coming into the world of God the Son in the opening verses of his Gospel. “The Word became flesh and dwelled among us.” God came into the world as a man. Why? Why this extraordinary and profoundly world-changing event, the greatest of all conceivable miracles and the deepest of all possible mysteries: that God the Son, the creator of heaven and earth and all that they contain, should take to himself a human nature, be conceived in the womb of the virgin Mary, be born a human baby and live a human life, suffer and die as only a human being could, and rise to new and everlasting life again as a human being, without ever or in any way, ceasing to be God in all the infinity of his divine nature? Why did it happen that the eternal God, while remaining God, became as well, a human being? Cur Deus Homo.

As I said, it is an important question – to answer it correctly is to come near to understanding the heart of the Christian message – and I suspect most Christians do know the answer to the question even if they have never thought about it in quite this way or ever had to fashion an answer to this very question. But even Christians can wonder from time to time if God couldn’t have saved his people in some other way? And there have been Christians who have thought that God could simply have forgiven our sin, without the incarnation and without the atonement. His love and grace are such, are they not, that he could simply forgive us. We don’t require some great thing of others before we forgive them; or at least we shouldn’t. And if we shouldn’t why should God? Why did God go to such lengths to forgive us? Why did he require this of himself? Cur Deus Homo; why did God become a man?

In Christian theology this question concerns what theologians call “the necessity of the atonement.” Precisely why was it necessary for God to become man and die on the cross? And Christian theologians have given different answers to that question through the years. They did not typically deny that it was necessary for God to become man, but they explained why it was necessary in different ways. It is fair to say, however, that Anselm’s answer to the question Cur Deus Homo, especially once it was perfected by the Protestant Reformers, became the standard answer, the answer of the largest number of faithful theologians, and certainly the unstudied opinion of most devout Christians. The reason, simply put, is that it seems very clearly to be what the Bible actually says and not once or twice but many times and what the Bible implies in many of the most well-known and best loved texts in Holy Scripture, including John 3:16.

Now, it is obvious, one would think undeniable, that the reason Christ came into the world was that God loves the world. That is what John says. It was love that sent God the Son into the world, or, as the hymn writer has it, love came down at Christmas. But to say that is not to answer our question: Cur Deus Homo. Why did God, loving the world, send his son into the world? Love was the reason for the incarnation but why was it necessary? Was there no other way that God’s love for the world could be expressed? No other way he could secure our salvation? As Anselm himself put the question:

“Is not the omnipotence of God everywhere enthroned? How is it, then, that God [had to] come down from heaven to vanquish the devil?” [I, vi]

In other words, if God can do everything, couldn’t he have done this in some other way? Remember, what the incarnation means. God the Son became a man, yes; but he lived as a man incognito, unrecognized as Godso much so that many not only did not recognize him as God, they didn’t even think he was a good man – he suffered as a man and finally, as a man, he died in ignominy and terrible pain. The incarnation of God the Son can never be understood apart from its purpose. As the angel told Matthew, as we read earlier in the service, he was to name his son Jesus because he would save his people from their sins. And as Jesus himself would later say, “The Son of Man came not to be served but to serve and to give his life a ransom for many.” The incarnation, God becoming man, was not an end in itself; it was the means to an end and the end was that Jesus would die on the cross for the sins of men.

So, the question Cur Deus Homo, why did God become man, is actually the question: why did God become man so that he could suffer and die for the salvation of men? That is what John says here, “God gave his only Son so that whoever believes in him should not perish but have eternal life.” And, of course, John will say many more things along the same line. He will quote Jesus saying, “I am the good shepherd. The good shepherd lays down his life for the sheep.” [10:11] He had to be a man to be the good shepherd who would lay down his life for the sheep.

Why did God’s love require that God the Son should become a man to suffer and die for the sins of men? That is the question Anselm was asking when he wrote Cur Deus Homo. Why this ineffable mystery of God becoming a man and why this terrible suffering that he endured; why was it necessary?

In Christian theology through the ages, the question has been answered primarily in one of two ways. The first answer, given by such notable theologians as Augustine and Thomas Aquinas goes by the name “hypothetical necessity.” That is, the incarnation and the atonement – the cross – were hypothetically necessary. That is, God might have forgiven sin and saved his people without atonement, without Christ’s suffering on the cross, without his death and resurrection – he might have accomplished our salvation by some other means – but God chose this way – the way of the incarnation of the Son and his suffering and death on the cross – because in his wisdom he judged it to be the best way. It wasn’t the only way, but it was the best way. It was the way that produced the greatest advantages for us and the way that displayed God’s love most clearly and powerfully. God could have saved us without the Son coming into the world and dying on the cross but in fact this is how he chose to save us. Incarnation and atonement were necessary only in the sense that God’s in his wisdom judged them to be the best way to save his people from their sins. The principal reason why they answered the question this way was to defend God’s omnipotence. Since all things are possible with God, so the argument goes, he could have secured our salvation in some other way.

The other answer, the one I wish to recommend to you this morning, is that God, having in love decided to save his people from their sins, had to save them in the way in which he did. There was no other way in which he could deliver us from sin and death apart from the incarnation of the Son of God and his death on the cross. This is the view that goes by the name of the absolute necessity of the atonement. That is, the incarnation of God the Son and his death on the cross were absolutely necessary if we were to be saved, delivered from our sins and given entrance into heaven. There was no other way in which we might be saved but this way. This conviction also has had its able defenders among the great theologians of the church. Among the church fathers, Irenaeus in the 2nd century taught the absolute necessity of incarnation and atonement. Anselm was its champion in the medieval church. And most of the great Protestant theologians have held this view.

Now we must be careful here. When we say that God had to save us in this way – by the incarnation of his only Son and by his Son’s death on the cross, we are certainly not saying that God was subject to some rule or law outside of himself. There can be no rule or law outside of God. What made the incarnation and the atonement absolutely necessary was precisely God’s own nature, his perfect holiness, justice, wisdom, goodness, and love. The necessity results only from who and what God is, what sort of person he is.

This is how Anselm himself made the argument for the necessity of the incarnation. If anyone imagines, he says, that God can simply forgive sin in the same way that we forgive others “he has not yet considered the seriousness of sin.” [I, xxi] And, of course, in this Anselm has the Bible on his side. There is an absolute antithesis between God and sin. We often forget this, we often ignore this, but the Bible tells us that it is so. He hates it, the Bible says. All the attributes of his character are offended by it. He must punish it. He cannot accept its validity as if Satan has equal rights with himself. [Bavinck, Ref. Dogm. III, 371-372] And lest you wonder if or why this should be so, consider this.

Sin is more than simply an attack on God’s honor or a violation of his standards. Sin is an assault on the very idea of right and wrong, on the very reality of justice, of goodness and of evil. If God were to ignore or wink at sin, at the violation of goodness, truth, justice, and love, if he were to excuse all the wrong that human beings do, sweep it under the rug as it were, the whole moral order of the world would collapse. Nothing is wrong, nothing is evil if there is no consequence, no punishment attached to it. The entire moral universe in which we live would become meaningless if sin were not punished in the nature of the case.

We bear witness to the essential connection between retribution and morality every day with all of our judging thoughts and with the words that we speak in criticism of other people. Sin ceases to be sin, wrong ceases to be wrong, if the one committing the sin or doing the wrong is not liable to be punished for having done so. The distinction between right and wrong ultimately depends upon the reality of punishment and reward. After all, what would it mean to say that something done by human beings is wrong or evil if it weren’t answered with an appropriate, an equivalent punishment, some consequence from which human beings recoil. Sin, Isaiah reminds us, has made a separation between ourselves and God. It must because our sin is an offense to his very nature and being. He recoils from it and that recoil, his separation from us on account of our sin, is the punishment of sin. And we are like God in that way because we are made in his image. We expect, we demand that sin be punished. We may be hypocritical in making that demand, we may often have very faulty opinions about what is sinful and how it ought to be punished, but that wrong behavior should pay a wage we all agree. It is one of the deepest convictions of human life, but that conviction depends entirely on the existence of a holy God who punishes sin and who has imprinted his nature upon human beings. If God were to fail to punish sin, if God were to tolerate it, if God were not to recoil from it, what would it mean to say that something, anything was sinful?

Take a current example. We are, as a society, passing through an unprecedented paroxysm of anger and disgust directed at public men, politicians, film and television stars, and sports figures principally, who have been exposed as abusers of women. Day after day someone else hits the news. Men are losing their high-profile jobs, are being shamed in the press, ridiculed by the late- night comics, and are seeing their carefully manicured reputations reduced to tatters. They must face a future defined by public disgust. That is sin and that is the punishment of sin. But what would happen if, instead of being fired, humiliated, and saddled with the reputation of a pariah, the society, the media, and the public were to say, “Well, who cares; who are we to judge; let’s not hold this against them”? Or worse, what if we were to say, “One man’s behavior is as good as another’s.” What would happen if no one lost his job, no one lost his reputation, and no one was exposed to humiliation and alienation?

First, the victims themselves would have been utterly abandoned and their sense of violation trivialized. It would be their fault for having complained. They would in effect be judged small-minded to expect others to respect their persons, their bodies, or their personal space. They would have been the ones punished rather than those who sinned against them. Sin always does harm, so who would it harm if the sinner himself were not punished? The victim of course; the only one left; and then society as a whole as it dealt with the result of the disappearance of any meaningful distinction between right and wrong. But, more than that, the entire society would soon descend into moral chaos. Nothing would be wrong any longer, at least in any meaningful sense. What does “wrong” mean, after all, if such behavior is accepted, or in effect approved, or even forgiven without consequence? There have been times and places in human history when the distinction between right and wrong has been virtually abandoned in the society, and those have been the darkest moments in the history of human life.

But if that is true of human society and its own judgments of human behavior – even human society whose views of sin are so often mistaken and corrupted – how much more must this be true of God upon whose holiness and justice all human moral order absolutely depends. Human beings take the essential connection between crime and punishment for granted, but they should not. Without God, without a foundation for moral order in the universe there can be no moral order. The very idea loses all its meaning. If there is no judgment there is no morality; but there cannot be judgment without a judge. And God is a perfect judge, a judge who, as the Bible says, will not clear the guilty.

If you and I are deeply offended when a criminal escapes punishment, when he flaunts the law and suffers no consequence, if we punish our children for their misbehavior, how much more would the holy God feel the offense if sin, which we being his creatures is an attack on him. Where does this moral consciousness come, where this connection between evil and retribution from except from God? Evolution certainly does not explain it, as the NYU philosopher, Thomas Nagel, admitted to the consternation of his atheist fellow travelers, in his recent book Mind and Cosmos. But if this universal human conviction comes from God, then surely God himself, his nature, his character explains why sin must pay a wage.

Therefore, to deny that God must punish sin is to deny the very nature of God and the very nature of sin. This is why, as we read in Hebrews 9:22, God’s people were schooled in the principle that “without the shedding of blood there is no forgiveness of sins.” God’s very nature as holy, as just; his position as the author of goodness and as the avenger of evil, his role as the judge of all the earth and defender of righteousness, made it necessary that he should punish sin if he were to forgive it. Because of God’s transcendent holiness he must hate sin and hating sin he must deal with it in justice. That is why the law of God demands that those who violate it be subject to a curse, that is, to a punishment. This principle is key to the entire explanation of salvation in the Bible. The sinner is subject to punishment and so forgiveness absolutely requires punishment. God himself told us that and God cannot lie. If we are cursed for our disobedience to God then somehow that curse must be removed from us if we are to be made right with God.

This was Anselm’s argument. It would violate God’s very nature to treat the sinner as if he were not a sinner, to ignore the wrong that had been done, or to allow his majesty to be violated by his own creatures with impunity. For this reason, we are told repeatedly in the Bible that God will not clear the guilty. If anyone is to be saved, therefore, he must first be made non-guilty. How, but by the vicarious, the substitutionary sacrifice of Christ?

Now it may seem presumptuous for men to say that there are things that God cannot do. But it is only to confess God to be God that we say, as the Bible teaches us to say, that God cannot lie (Titus 1:2), that he cannot deny himself (2 Tim. 2:13), that he cannot look upon iniquity (which is to say that he cannot be indifferent toward it), that he cannot give his glory to another (Isa, 42:8), that he cannot dwell with the wicked (Psalm 5:4), and that he cannot allow himself to be defamed (Isa 48:11). These divine “cannots” are simply the inevitable implications of God’s nature. Were he to be able to do such things he would not be God!

This is the idea that lies behind the statement in Hebrews 9:23 that the Levitical sacrifices of the OT were ordered according to the heavenly pattern but that the heavenly things themselves had to be purified by better sacrifices than those. That is, the nature of God himself required that Christ – the God-Man – suffer and die on the cross to secure salvation. The heavenly things, that is the holiness and justice of God himself, required an infinite and a perfect sacrifice that no mere animal, no mere man indeed, could ever make. In that entire passage the problem is the guilt of sin and the solution, the only possible solution, is the atoning sacrifice of the Son of God.

How, Paul asks in Romans chapters 2-5, could a holy God acquit or justify the ungodly? Would not that be unjust of him; dishonest; a travesty of jurisprudence? And the answer Paul gives to that question, as we all know, is that Christ’s sacrifice, his death in our place on account of our sin, satisfied the justice of God – proper punishment having been inflicted upon our sin – and made it possible for God to be at one and the same time just and the justifier of the one who has faith in Christ Jesus. The cross made it possible for God to forgive our sins without violating his own holiness!

The cross is the supreme demonstration of the love of God. We are told that again and again.

“In this is love, not that we have loved God but that he loved us and sent his Son to be the propitiation for our sins.” [1 Jn 4:10]

But would the cross be the supreme demonstration of God’s love if it weren’t actually necessary? And why propitiation, the turning away of God’s wrath if that were not necessary? The incarnate God dying on the cross was the only conceivable means of satisfying divine justice. Only the incarnate God could die for the sins of the whole world and only by dying could he satisfy the requirements of divine justice offended as it had been by our sin. The simple fact is that such a tremendous thing was done – that God himself should come into the world as a man, live incognito, suffer terribly and die on the cross – I say that such an astonishing, unprecedented, stupendous thing was done is proof that it had to be done, that there was no other way to remove the guilt of sin and to deliver us from death to eternal life. Only a man could die but only a God-Man could die a death sufficient to atone for the sins of the whole world. And so this is what was done.

And why was this done? John tells us. Because God so loved the world! We forget this, we take it for granted, but it is the most remarkable fact about you, a fact that absolutely transforms the meaning of your life. God who made heaven and earth loves you. He loves you so much he was willing to make the greatest conceivable sacrifice for you. Would you surrender your only child to humiliation and a horrible death to save someone you loved? God surrendered his beloved Son to save a world of his enemies, of selfish, petty, egotists like you and me. That is love we can scarcely conceive! Christ was sent and Christ came for you, that you might live with God forever! If that is true, and it is, it is the single most significant fact about your life, something you ought to be remembering, thinking about, pondering and applying to your life every single hour of every single day. It invests your life with splendid meaning, value, and promise. If the greatest thing ever done in this world was done because God loves you, then your life, your very self, must be a very great thing indeed!

In October of 1996 a service was held in St. Martins-in-the-Fields Church in central London to celebrate the life of the English novelist Kingsley Amis. During the service Amis’ son, Martin Amis, also a novelist, told of a conversation his father once had with the Russian novelist Yevgeni Yevtushenko. Yevtushenko, perhaps assuming that all Englishmen were Christians, asked Amis if it were true that he was an atheist. “Well, yes” said Kingsley, but then added, “But it’s more than that. I hate him.” [Cited in Sinclair Ferguson, “Preaching the Atonement,” The Glory of the Atonement, 429] Ignore for a moment the delicious logical inconsistency of a man who hates a person whom he does not believe exists. Concentrate instead on the brute fact that Jesus Christ divides the human race into two communities: those who love God and those who hate him. There is not a third class of human beings. As one theologian put it, “the cross of Christ is man’s own glory or it is his final stumbling block.” [Denney, The Death of Christ, 243-244] If the incarnation and atonement of the Son of God are anything, they are everything. You either love God for his great love and sacrifice for you or you hate the very idea that he should have to do so much to save you from your sin. No human being can really believe that God loved us and gave himself for us and not love him in return.

Say it to yourself right now: “I love God because he first loved me; and I love the Son of God because he gave himself for me! I do and I always shall.”