1 John 2:4

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 1:8

If we say that we have no sin, we are deceiving ourselves and the truth is not in us.

1 John 1:6

If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not practice the truth;

Hosea 8:2-3

They cry out to Me,
“My God, we of Israel know You!”

Titus 1:16

They profess to know God, but by their deeds they deny Him, being detestable and disobedient and worthless for any good deed.

James 2:14-16

What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him?

If we say that we have not sinned, we make Him a liar and His word is not in us. Cross references: 1 John 1:1 : John 1:1f; 1 John 2:13, 14 1 John 1:1 : Acts 4:20; 1 John 1:3 1 John 1:1 : John 19:35; 2 Pet 1:16; 1 John 1:2 1 John 1:1 : John 1:14; 1 John 4:14 1 John 1:1 : Luke 24:39; John 20:27 1 John 1:1 : John 1:1, 4 1 John 1:2 : John 1:4; 1 John 3:5, 8; 5:20 1 John 1:2 : John 19:35; 1 John 1:1 1 John 1:2 : John 15:27; 1 John 4:14 1 John 1:2 : John 10:28; 17:3; 1 John 2:25; 5:11, 13, 20 1 John 1:2 : John 1:1 1 John 1:2 : John 1:4; 1 John 3:5, 8; 5:20 1 John 1:3 : John 19:35; 2 Pet 1:16; 1 John 1:1 1 John 1:3 : Acts 4:20; 1 John 1:1 1 John 1:3 : John 17:3, 21; 1 Cor 1:9 1 John 1:4 : 1 John 2:1 1 John 1:4 : John 3:29 1 John 1:5 : John 1:19; 1 John 3:11 1 John 1:5 : 1 Tim 6:16; James 1:17 1 John 1:6 : John 8:12; 1 John 2:11 1 John 1:6 : John 8:55; 1 John 2:4; 4:20 1 John 1:6 : John 3:21 1 John 1:7 : Is 2:5 1 John 1:7 : 1 Tim 6:16 1 John 1:7 : Titus 2:14 1 John 1:8 : Job 15:14; Prov 20:9; Rom 3:10ff; James 3:2 1 John 1:8 : John 8:44; 1 John 2:4 1 John 1:9 : Ps 32:5; Prov 28:13 1 John 1:9 : Titus 2:14 1 John 1:10 : Job 15:14 1 John 1:10 : John 3:33; 1 John 5:10 1 John 1:10 : 1 John 2:14 end of crossrefs

1 John 2:9

The one who says he is in the Light and yet hates his brother is in the darkness until now.

1 John 4:20

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.