The perfect tense of we have not sinned shows that the reference is to the result of an act in the past. The clause states that “we” have never actually done anything sinful, and consequently are free from the resulting guilt. As such it differs from verse 8a, which refers to the quality of sinlessness. For this verb compare the noun in 1 John 1.7.

In many receptor languages the noun ‘sin’ and the verb ‘to sin’ are related forms, as they are in Greek and in English, but in some cases such forms, though existing, have different connotations. Thus one American Indian language has a specific noun for ‘sin’ but cannot use the related verb, which refers only to sexual misbehavior; hence ‘to sin’ has to be rendered by ‘to do bad.’

We make him a liar (compare also 5.10) is more forceful than the two preceding refutations, “we lie” (verse 6), “we deceive ourselves” (verse 8). “Him” again refers to God, who has said that men are sinners and need forgiveness, and who has acted and still acts accordingly. Consequently men who deny that they have sinned state as a fact what is not a fact according to God’s own words and deeds.

The clause has been rendered ‘we declare him to be a liar,’ ‘we are looking on God as one who habitually lies,’ ‘it is the same as saying that he lies,’ ‘God is lying according to us.’ Simply to use a causative derivation of ‘to lie’ is not satisfactory, as a rule.

His word is not in us. The rendering of “to be in” should parallel the one used in verse 8c as closely as idiom allows.

His word, or ‘what he has said,’ ‘what he has told (us),’ refers to God’s revelation, which culminates in Jesus’ life and preaching as told in the Gospel. The Johannine writings often stress the influence and character of God’s word, stating that it cleanses man (John 15.3), and that it is closely related to “life” (John 5.24), or to the victory over the evil one (1 John 2.14b), or to “truth” (John 17.17). The latter is also the case here, in the parallel verses 8c and 10c. Taken together they serve to bring out that God’s word reveals God’s truth, showing who God really is and how he behaves towards mankind. For the rendering of word see also 1 John 1.1c.

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 .