1 John 2:4

2:4 The one who says “I have come to know God” and yet does not keep his commandments is a liar, and the truth is not in such a person.

1 John 2:22

2:22 Who is the liar but the person who denies that Jesus is the Christ? This one is the antichrist: the person who denies the Father and the Son.

1 John 4:20

4:20 If anyone says “I love God” and yet hates his fellow Christian, he is a liar, because the one who does not love his fellow Christian whom he has seen cannot love God whom he has not seen.