1 John 2:4

4 he who is saying, `I have known him,' and his command is not keeping, a liar he is, and in him the truth is not;

1 John 2:4 Meaning and Commentary

1 John 2:4

He that saith I know him
God or Christ, as the Gnostics did, who pretended to great, even perfect, knowledge of divine things:

and keepeth not his commandments;
which the above persons had no regard to, and as many who profess great light and knowledge in our days show no concern for:

is a liar;
he contradicts what he says, and gives the lie to it; for though in words he professes to know God, in works he denies him, and which betrays his ignorance of him:

and the truth is not in him;
there is no true knowledge of God and Christ in him; nor is the truth of the Gospel in his heart, however it may be in his head; nor is the truth of grace in him, for each of these lead persons to obedience. The Ethiopic version renders it, "the truth of God is not with him"; (See Gill on 1 John 1:8).

1 John 2:4 In-Context

2 and he -- he is a propitiation for our sins, and not for ours only, but also for the whole world,
3 and in this we know that we have known him, if his commands we may keep;
4 he who is saying, `I have known him,' and his command is not keeping, a liar he is, and in him the truth is not;
5 and whoever may keep his word, truly in him the love of God hath been perfected; in this we know that in him we are.
6 He who is saying in him he doth remain, ought according as he walked also himself so to walk.
Young's Literal Translation is in the public domain.