Whoever remains in him doesn't sin. Whoever sins hasn't seen him, neither knows him.
Hath not seen him — It is no unusual thing with this apostle, both in his gospel and in his epistles, to put occasionally the past for the present, and the present for the past tense. It is very likely that here he puts, after the manner of the Hebrew, the preterite for the present: He who sins against God doth not see him, neither doth he know him-the eye of his faith is darkened, so that he cannot see him as he formerly did; and he has no longer the experimental knowledge of God as his Father and portion.