What Christians Know


1 John 5:13-21

This morning we complete our series of sermons in the first letter of the Apostle John.


Text Comment



v.18

John sums up by repeating points he has made already in the body of the letter. Once again, John’s categorical and unqualified manner of speaking should not confuse us. He does not mean that Christians do not continue to sin, but that their lives are no longer defined by sin, that there has been in them a decisive break with sin. The new birth is not an isolated experience; it has a continuing effect in a person’s life; it changes him or her morally. Those who have born of God will never leave off following the Lord Jesus Christ. This is, of course, said in contrast to what has been said in the immediately preceding verses. There are those who commit the sin unto death, but those who have been born again do not and will never commit that sin. They will never leave the Lord Jesus. The dire warning of vv. 16-17 need not trouble faithful believers.


And why is that? Because “he who was born of God” – almost certainly a reference to the Lord Jesus – protects him. Remember the Lord’s remark in the Gospel of John: speaking of himself as the shepherd of the sheep he said, “I give them eternal life, and they shall never perish; no one can snatch them out of my hand.” [10:28-29]


We must have that assurance of the Lord protecting us because we have an adversary who would destroy us if he could.


v.19

There is a single alternative: one is either in the world or in the family of God, one cannot be in both at the same time and one must be in one or the other. People imagine that they are the captains of their own fate, but, in fact, they are the servants of the devil, in his grip and under his control (Stott, 193). This is his world, or is for the time being, and they belong to him and are subject to him. We already read in 2:17 that this world is passing away, but whoever does the will of God abides forever.


Notice also that the world lies in the power of the evil one. It is not struggling to break free; it is content to do its master’s will. As the Bible everywhere teaches, such is the mystery of unbelief and sin. Man, left to himself, would rather rot and die in sin rather than serve God if that means he must live in righteousness.


v.20

Remember we have been told what John means earlier in the letter. The Son of God has come in the flesh (4:2), the very thing denied by Cerinthus and the false teachers who had troubled these Christians; he came by water and blood, which is to say he was the Son of God at his baptism and still the Son of God on the cross. A real incarnation, a real human nature embraced by the Eternal Second Person of the triune God. And by his Spirit he has given his people a spiritual intelligence or understanding by which they may discern truth from error, the real from the irreal.


As one wise commentator puts it, the Christian religion is both historical and experimental or experiential. It concerns what theologians refer to as historia salutis (the history of salvation) – the events by which the church has been redeemed by the grace and power of God, the birth, life, death, resurrection, ascension, and coming again of the Son of God – and ordo salutis (the order of salvation) – the events that transpire in an individual life when that redemption of Christ becomes a living power in him or her. [Stott, 194] Long ago Christ came, but only recently, in the course of our lives, have we been forgiven our sin, have our minds been illuminated to see the truth about God and ourselves, have our wills been bent toward the will of God.


As we have often pointed out as we have made our way through this letter, there are many similarities of theme and statement between First John and the Gospel of John undoubtedly because they have the same author. The last part of v. 20 is another. It reads very like John 17:3: “And this is eternal life, that they know you the only true God and Jesus Christ whom you have sent.”


v.21

In the context of the letter and of the historical situation, so far as we understand it, “idols” here does not seem to refer to physical images, as if these people would have been tempted to bow down to wood and stone. Rather false conceptions of God and of Christ, the conceptions that are at variance with what these Christians had been taught are what are meant. [Bruce, 128]


As we have often said in these sermons, John’s argument is meant to confirm us in the knowledge of our salvation. He wants us to know, as he says in 5:13, that we have eternal life. “Know” is a very important word in 1 John. The two primary verbs meaning “to know” in koine Greek occur many times in this short letter (almost 40x in fact), as they both occur many times in the Gospel of John, and we also have the word “confidence” as in 5:14, which John used 4 times in the letter and which makes the same point. John wants us to be certain of things.


So it is not a surprise that as he draws his letter to a close we should find ourselves once more reminded of what we know. “We know”, v. 18; “We know,” v. 19; “And we know” v. 20.


But do we know these things, or, better, do we know them? There is perhaps no more significant idea shaping modern Western life, that is the life of Western civilization in its modern form, than the fact/value distinction, also called the knowledge/belief distinction or the reason/faith distinction. According to this way of thinking knowledge is objective andhas to do with facts, the sort of things of which all men can be absolutely sure. Objects fall, hot air rises, the earth revolves around the sun, such facts as those. People can know such things. Knowledge is a word reserved for things that are certain and the only things we know for certain are the things that science and reason can prove. On the other hand, beliefs are subjective. They are opinions, valid only for the people who happen to hold them. In our culture today, for example, many argue that we can know that all living things, including human beings, evolved from primitive forms of life and that those primitive forms themselves evolved from chemicals that existed on the earth long ago. We can know that. Science is supposed to have proved that. Whether it has done anything of the kind, of course, is a fair question and one that more and more people are asking. But, be that as it may, when people claim that God created the heavens and the earth and the creatures that fill them, that is a matter of subjective belief only. It is not knowledge; it is only opinion. It is not a fact; it is only a person’s particular value-judgment.


In this way human experience is divided into two separate and even contradictory domains. Human beings live in both – they can’t help it – but only in one can they claim to know anything, to be certain of anything. Darwinian evolution, we are told, is public truth; Christian ideas about a creator and the creation of mankind are beliefs, opinions, nothing more. However useful it may be to those who hold such a belief, it cannot be made the basis of any claims that bear on all human beings at once. “Values may be personally meaningful, may be part of our cultural tradition, but ultimately they express something about ourselves only, not about objective reality.” [Nancy Pearcy, “Intelligent Design and the Defense of Reason,” Darwin’s Nemesis, 228] Science gives us facts; God, Christ, and heaven and hell are personal preferences.


Most of you are Christians and you probably struggle to realize how deeply this bifurcation of thought, this distinction between facts and values has settled in the modern mind and, in particular, in the minds of young people in our western world. Professor Peter Kreeft of Boston College writes that the students coming into his classroom are


“perfectly willing to believe in objective truth in science, or even in history sometimes, but certainly not in ethics or morality.”


It is true that there are some among the cultural elite who would admit in public that beliefs and values are really simply fantasies; they are illusions, however well-intended, and no educated person should imagine that they should be taken seriously. But most people who actually believe that they should distinguish between things that can be known – such as the facts of science – and things that can only be believed – such as religious truth – that is, people who still support the fact/value distinction, are unlikely to say such a thing publicly because it would offend too many people. Most people still think that there are real facts, that there is real truth, that there is knowledge, in other words, that cannot be demonstrated in a test tube or by the calculations of a computer. That human life is precious, that certain behaviors are wrong and others right, that love is of supreme importance, and so on. They would say that they know such things to be true. The typical university professor would disagree, of course. They would allow that people are free to hold their religious beliefs but that no one should pretend that such beliefs constitute knowledge.


Such is our world. And to be sure we should be among the first to admit that there is a great deal of so-called knowledge in this world that is nothing of the kind. I have been reading of late David McCullough’s The Path Between the Seas, the story of the building of the Panama Canal. You may remember that the French tried first and failed. It was an effort led by a wildly popular figure, the man who had successfully dug the Suez Canal and he talked thousands upon thousands of ordinary Frenchmen into investing in this new effort. They were all going to make a lot of money and, at the same time, add to the glory of France. But the effort failed, catastrophically so, and a great many people who could not afford to lose anything, lost everything. They knew it was a sure-fire investment, except it wasn’t. What they took for knowledge was, in fact, only one man’s opinion and a wildly inaccurate one at that. Sometimes what people claim to know really is just an opinion, a preference.


But then here comes John saying that we know these things about Christ, the Son of God come in the flesh, and about the world being the domain of the devil, and about our own salvation. Is this knowledge in the strong sense or mere opinion? John certainly does not seem to think that our knowledge of these things is mere opinion or preference. Things have happened and you can know that; God has revealed himself to the world in Jesus Christ and you can know that; God loves you and you can know that; Christ has redeemed his people by his death and resurrection and you can know that; Your life has been transformed by the grace of God and you can know that too. You don’t simply think this to be true or hope it to be true; you know it to be true. But is that possible? Many in our world today say that no one can really know any such things. In the nature of the case there is no such human knowledge.


You may be interested to know that this question, this problem if you will, has been carefully treated in Christian writing and preaching since the very beginning. It had to be because from the beginning there were many who were arguing publicly and intelligently that the Christian message was not true, that it was a fantasy and a superstition. How do Christians, then, know that it is not a superstition, but rather an account of reality, hard as rock? Philosophers call this epistemology, the study or, better, the justification of knowledge. How do we know anything to be true and, in our particular case, how do we know that Christ is the Son of God and we are his people and because of him we are going to heaven? How could anyone know any of this for sure when we can’t see Christ or heaven?


After all, there are many others who are just as sure of the truth of their religion or just as sure that God does not exist at all. To know that we are right is, inevitably, to know that they are wrong. Can we know that? What is more, there are people, as John has admitted in vv. 16-17, who used to be Christians and decided at some point along the way that the Christian faith wasn’t true. The very arguments that persuaded them at one point, failed to persuade them later. So how can we be sure of these things?


Now there are many answers to these questions: many important and entirely reasonable answers. It has been pointed out through the ages and again recently in a magisterial study by the English scholar Richard Bauckham (Jesus and the Eyewitnesses) that the Christian faith rests upon events that occurred in history and that were witnessed by many people. The New Testament makes a great point of this eye-witness testimony and so does John himself, himself one of those eyewitnesses. They saw the things of which they spoke; they saw and heard the Son of God; they saw him die; they saw him alive again on the third day in a similar but not identical body; they saw him ascend to heaven; and they heard him say he was coming again. They received the message from him that they were to deliver to the world. They saw the miracles. This testimony is often minimized but no one should misunderstand that it is the bedrock on which the foundation of the Christian faith has always rested. A great many of the things we know we know because we have been told by people we trust. Everyone in that sense is in the same boat. I simply remind you that a great many people have looked into the matter and come away convinced, even at this great distance, that it is more reasonable to believe that eye-witness testimony than to disbelieve it.


Or we might refer to the argument from coherence. The Bible in a way that is simply astonishing, utterly unlike other holy books, describes the world as it actually is and human life as we find it to be, warts and all. There is no other book, religious or secular, that still today commands the loyalty of hundreds of millions simply because it is so manifestly and relentlessly truthful. And I could go on and on enumerating arguments to justify a Christian saying that he or she knows that Christ is the Son of God and that the good news of salvation in his name is true in the ordinary sense of the term, that is, it is a fact, it is what is real. But that is not what John does here.


John rests our knowledge on another foundation. He certainly does not deny that Christian faith is eminently reasonable and that a great many solid arguments could be advanced on its behalf. But in John’s mind, first and foremost knowledge is personal, immediate, and intuitive. In fact most of any person’s knowledge is of this type. When we say that we “know” someone, we mean that we have met the person. “Yes, I know him,” may mean simply, that I am acquainted with the person. But, if I say I know him, I may mean something more. I may mean that through long association and through shared experienced I have come to have an intimate knowledge of the person; I am aware not only of what he looks like, but of his character, his sense of humor, his own life history, his strengths and weaknesses. I know him. Husbands and wives come to know one another in this way. They remain human beings and their knowledge is not exhaustive, but there is much that they really do know because of the long and intimate relationship they have had.


Well it is this kind of knowledge that Christian believers have: immediate and personal and intuitive and self-authenticating. They know God because he has made himself known to them; he has met them and they have in turn met him; they know Christ Jesus because he has revealed himself to them.


When God appeared to Adam in the garden, or to Moses at the burning bush or in the Tent of Meeting, or to Isaiah in the temple, neither man for a single moment quibbled with himself about how he could know that this is really God. As the saying goes, “When in the jungle a man might mistake the growl of a hyena for that of a lion, but when he hears the lion roar he knows damn well it’s a lion!” Madame Curie knew she was on to something when she saw her experiments begin to glow; no one could doubt the existence of radium any longer. And at Trinity Site in the New Mexico desert in July of 1945, when the first atom bomb detonated, no one could any longer doubt the power stored in the interior of an atom. In the same way no one could doubt the resurrection of the Son of God who saw the risen Christ standing right in front of him and no one can doubt the reality of God and his grace who has met God and experienced the power of his grace.


Everywhere in the Bible and everywhere in the history of the church this is how knowledge of Christ and salvation comes: through spiritual intuition, through personal encounter between God and man, and through self-authenticating divine revelation. That is what John means when he speaks of being born of God and of being given an understanding that that we may know…


Very few people who are Christians today, very few who have ever been Christians went looking to evaluate the Christian faith to see if it were true, considering the arguments for and against and then coming to a conclusion. I don’t deny that the Lord might use such a process and even that he has in come cases, but very rarely. Very little knowledge comes to any human being that way in fact. We hardly ever learn what is true by investigation. Some things come to be known that way, but very little of real consequence for human beings, unless you are willing to say that the effect of an aspirin or the use of a cell phone is the meaning of life. How do you know that your mother and father are your parents? How do you know that they love you? How do you know that such and such a person is your friend? How do you know that what you said or did was wrong and that is the reason why you are ashamed? None of this can be discovered in the lab, but it is this kind of knowledge from which our lives are made. It is the kind of knowledge from which every human life is made.


Who you are, what your life means, what kind of person you are; where you are going, how you might know God; none of that is knowledge susceptible to demonstration in a test tube, but it is vastly important knowledge. Everyone knows all this only in the way of the personal and immediate and intuitive encounter of persons. Well so it has been with us and God our Father and Christ our Savior. They came to us and introduced themselves and we began to get acquainted. It is perfectly understandable that someone who does not know God is not impressed by our testimony about him. Some things must be seen to be believed. Some people must be met to be known.


I once thought I was a basketball player. I was making progress up through the ranks of teams in my school. I could see that I was improving at every phase of the game. I couldn’t jump, of course; I was unfortunately affected by an unusual degree of gravity. Still, I had hopes. But once I found myself in a game guarding a fellow two years younger than I. And meeting him clarified everything. In a moment of stunning intuition I realized that I was no basketball player and never would be. This boy could jump. I found myself guarding his sneakers throughout the game. Some things you know because you can’t help but knowing them.


And so it is with us and God and Christ. We know because we know. It may sound weak to some, but remember, that is the only way anyone knows much of anything that is really important to a human being. I do not know why the Lord has not made himself more visible to the world. I do not know why the Lord Christ did not appear to the Roman emperor after his resurrection. I do not know why he has not provided the world with a demonstrative proof of his message, proof like you find in Euclid’s geometry or Einstein’s physics. I do not know why he reveals himself to some and not to others. But such is his will and such are the facts of life. It does no one any good to protest them. Rather everyone ought to seek from the heart of a loving God the knowledge of himself, a knowledge that he alone can give and promises to give to those who honestly and sincerely seek it from him.


“You will seek me and find me, when you seek me with all your your heart.” [Jer. 29:13]


“He who comes to me I will never cast out.” [John 6:37]


How else will someone come to know God? How else would it be possible to know that when you die you will go to heaven and not to hell? How else can you know that your sins are forgiven and that you are right with God? How else would it be possible to know those things, but that God should make himself known to you, and tell you these things? And because it is his word being spoken to you, you are convinced beyond the shadow of a doubt that they are true.


I read the other day of a German physicist by the name of Alfred Runki. He died young, 56 years of age, in 1983. He and his wife were devout Christians and devoted themselves to gospel ministry in their home and elsewhere. He had a ministry to professionals, university types, as well as to students. He had not been a Christian himself when he went off to university in Marburg. But he was invited to a Bible Study by an older man, a Russian émigré, who taught mathematics at the university. Runki later said that the Bible study itself had not been of much use to him, but when he heard the old Russian professor pray, he was deeply convinced that he was really speaking to someone. [BOT 239-240 (Aug – Sept 1983) 38-41]


In other words, this man found God because he heard someone else talking to him! And, then, of course, God introduced himself to Runki. The text at his funeral was from 1 John:


“Beloved, we are God’s children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is.” [3:2]


How do we know that? Because we know him! If you do not know him, do not rest until you do. And if you do know him, then live like it and let others meet him through you.