Romans 1:21
for although they knew God they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened.
Romans 1:28-30
And since they did not see fit to retain the knowledge of God, God gave them over to a base mind, to do what ought not to be done.
2 Corinthians 6:15
What harmony has Christ with Belial? Or what has a believer in common with an unbeliever?
John 8:55
But you have not known him; I know him. If I said, I do not know him, I would be a liar like you; but I do know him and keep his word.
John 16:3
And they will do these things because they have not known the Father, nor me.
John 17:3
And this is eternal life, that they may know you, the only true God, and Jesus Christ whom you have sent.