Throughout the book of 1 John, we see detailed treatments of three basic tests of genuine Christianity. They are the moral and ethical (keeping God’s commands), the familial (loving one another), and doctrinal (believing the truth). In this passage of his letter, we find John addressing the first two of these.
Now by this we know that we know Him, if we keep His commandments. He who says, ‘I know Him,’ and does not keep His commandments, is a liar, and the truth is not in him. But whoever keeps His word, truly the love of God is perfected in him. By this we know that we are in Him. He who says he abides in Him ought himself also to walk just as He walked. Brethren, I write no new commandment to you, but an old commandment which you have had from the beginning. The old commandment is the word which you heard from the beginning. Again, a new commandment I write to you, which thing is true in Him and in you, because the darkness is passing away, and the true light is already shining. He who says he is in the light, and hates his brother, is in darkness until now. He who loves his brother abides in the light, and there is no cause for stumbling in him. But he who hates his brother is in darkness and walks in darkness, and does not know where he is going, because the darkness has blinded his eyes
(1 John 2:3-11).
First we must deal with assurance of salvation in the context where we normally think of it. Remember the context of this letter. John is not addressing a tormented Christian, alone in his room, wrestling with a troubled conscience over some sin or affliction in his life. John is not addressing the sensitive believer in the midst of a panic attack. He is talking about a group of false teachers who have an utter disregard for the commands of God. In John’s mind, these issues are to be understood in terms of light and darkness; he is not discussing varying degrees of early twilight. His absolutism is refreshing in a relativistic era, in which our thinkers and theologians want all cats to be gray.
But biblical assurance is never achieved by looking within. First, we gain assurance by looking in faith to the perfect obedience of our Lord Jesus Christ. Secondly, our assurance is confirmed when we look at our lives and see an imperfect obedience (distinct from our previous rebellion), which imperfect obedience is accepted for Jesus’ sake. Only in this way will we avoid two errors: on the one hand, complacent resting in sin because of our supposed ‘justification,’ and on the other, frantically working to be ‘righteous enough’ in order to be assured of salvation.
We can see here that we know that we know — when we live in a distinct way from the false teachers (who say obedience is unnecessary), this gives us a genuine assurance. We can be assured because we resist false claims — the one who says he knows God and yet walks in darkness is a liar. Note what it does not say. It does not say that the one who falls down in the light is a liar, or the one who stumbles in the light is a liar. It refers to the one who walks in darkness. Then there is the love for God that His children have — if the believer keeps the word of God, in this we see the love of God perfected or completed in him. And finally, we can ask “what would Jesus do?” The one who claims to abide in Jesus must walk in the same way that He did. The point here is the ongoing imitation of Christ. But please note, this is not an imitation of the Jesus of popular imagination. The question is what “would Jesus do?”, and not “what would we like Jesus to have done?”
We should rejoice in our Christian faith, a faith in which the truth is always ancient, and the love is new every morning. There is no new commandment; the necessity of loving one another is not a novelty introduced later on in the Christian life. Every young Christian, with the water of baptism still on him, needs to be taught that Christians love one another. And old commandments, when they are obeyed, are new. Obedience in love is light, and lights the way. A man who refuses to love is in the dark and stumbles around in the dark. The one who walks in light can see the way. Loving the brothers is described as walking in the light. Such a man has no cause for stumbling (skandalon) in him. Those who walk in darkness (malice and hatred) have lost their way. One of the evidences that such people have lost their way is that they believe themselves to be in the light. Now obviously, if they think they are in the light, they must be using other criteria to make this determination. They must be appealing to their knowledge of their philosophy, or in some fashion be measuring themselves with themselves. “Whatever I see must be light. What I see is darkness. Darkness must therefore be light.”
As John would say to us if he were here, “Dear children, love one another.” But by means of the Scriptures, he is here, and he does say it.