The encouragement to pray for others is based on a great promise, namely, the promise that God will hear and “give… life for them that sin not unto death” (v. 16). John has spoken often in this letter of the need to pursue righteousness as one evidence that the individual involved is truly a child of God. But in spite of the fact that the individual Christian must and, in fact, will pursue righteousness, nevertheless, he will also sin and even from time to time become entangled in it. What then? Obviously, the Christian should confess sin and turn from it knowing that he has an advocate in Jesus Christ and that the Father is faithful and just to forgive him on the basis of Christ’s sacrifice and continuing intercession (1:9-2:2). But it is often the case that when he is in this state this is what the Christian least wants to do. So what then? Should he be left to himself to suffer the consequences of his sinning? Not at all, says John. Rather, those who are spiritual should pray in his behalf knowing that God will respond when they thus pray for others.
In all honesty it must be acknowledged that in this area Christians often fail grievously. For sin in a brother becomes all too often a cause for gossip rather than a cause for prayer. What is wrong in this case? The answer is in these verses, for they suggest that it is when a believer is himself in the will of God and is therefore praying according to the will of God that he will pray for others. John does not even use the imperative (“Pray!”). He uses the future indicative, saying that the spiritual person will intercede for the sinning brother.
It is hard to imagine anything more obviously in accord with the will of God than the restoration of a Christian who has become trapped in some sin. Yet, surprisingly, John seems to hesitate. His desire is obviously to encourage his readers to be bold in their prayers. He stresses confidence. But is it right, after all, that it is always God’s will to restore the sinner? Always? In verse 16 John seems to recognize that it is not always the case and therefore introduces an exception based upon a distinction between sin which is “unto [literally, toward] death” and sin which is not. “There is a sin [which is] unto death,” he says; “I do not say that [one] shall pray for it.”
But what is this sin that is “unto death”? Apparently, in John’s day and with his readers the phrase was a common one and was well understood, for John does not bother to explain it. But today the key has been lost, and opinion is widely divided in regard to John’s meaning. Four views are prominent.
1. The first view is that John is referring to some particularly heinous sin which God, so we are old, will not pardon. At first glance this seems to be suggested by a long history of divisions between various types of sin beginning with the Old Testament Scriptures. In the law codes of the Old Testament several distinctions are fundamental: a distinction between capital offenses and those that are not capital offenses, for example; or a distinction between sins of neglect or ignorance and sins of presumption or premeditation. This latter is the same kind of distinction that is made in modern law between murder in the first and murder in the second degrees. Rabbinical law further elaborated such distinctions, and in time the classification of sins as forgivable and unforgivable entered the Church. At this time it was spelled out as the difference between “mortal” and “venial” sins, a distinction common in Catholic theology.
The difficulty with this interpretation is that it is somewhat of an anachronism to apply the distinction between mortal and venial sins here. Moreover, it may also be said that such a distinction is simply not supportable from the pages of the New Testament and that John, even in this very letter, seems to contradict it (see 3:6, 9).