1 John 1:10; 1 John 2:4; 1 John 2:22; 1 John 4:20; 1 John 5:10

1 John 1:10

10 If we say that we have not sinned, we make Him a liar and His word is not in us.

1 John 2:4

4 The one who says, "I have come to know Him," and does not keep His commandments, is a liar, and the truth is not in him;

1 John 2:22

22 Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son.

1 John 4:20

20 If someone says, "I love God," and hates his brother, he is a liar; for the one who does not love his brother whom he has seen, cannot love God whom he has not seen.

1 John 5:10

10 The one who believes in the Son of God has the testimony in himself; the one who does not believe God has made Him a liar, because he has not believed in the testimony that God has given concerning His Son.