The connection between verse 5 and the preceding verse is this: if you commit sins, you set at naught Christ’s mission, for, as you know, he came to take away sins. Thus there is a contrast between the two sentences which may have to be marked explicitly, for example, by introducing verse 5 as follows: ‘You know, however, that he appeared…,’ or ‘But he appeared, as you know….’

He appeared: the pronoun, literally ‘that one,’ refers to Christ, see comments on 2.6. The tense used is the aorist, which shows that the reference is to Jesus’ appearance in history.

To take away sins, or “in order that he may take away sins” (compare John 1.29); the two occurrences should be rendered alike.

The plural of the noun shows that the reference is to specific sinful deeds; compare 1.9. To bring this out may require ‘to take away our sins’ (also found in a variant reading of the Greek text), ‘to remove our sins from us,’ ‘to free us from our sins.’ Where the noun must be rendered by a verbal form, one may say ‘to make them people who sin no more.’

And in him there is no sin is not dependent on you know. It is, therefore, to be rendered as a new, independent sentence. The present tense shows that the reference is both to Christ’s life among men in the past, and to his present life with the Father. For the force which in has here compare “in him there is no darkness” in 1.5.

The noun sin, now in the singular and without article, may refer to a sinful condition or character; hence renderings of the clause like, ‘he is absolutely without sin,’ ‘he does not and cannot sin.’

Quoted with permission from Haas, C., de Jonge, M. and Swellengrebel, J.L. A Handbook on The First Letter of John. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .