Romans 1:21
because, although they once knew God, they did not honor Him as God, or give Him thanks, but became silly in their senseless speculations, and so their insensible hearts have been shrouded in darkness.
Romans 1:28-30
And so, as they did not approve of fully recognizing God any longer, God gave them up to minds that He did not approve, to practices that were improper;
2 Corinthians 6:15
What harmony exists between Christ and Belial, or what is common between a believer and an unbeliever?
John 8:55
And yet you have not learned to know Him; but I know Him, and if I say I do not know Him, I will be a liar like you. On the other hand, I do know Him and I do follow His teaching.
John 16:3
They will do this, because they have never come to know God nor me.
John 17:3
Now eternal life means knowing you as the only true God and knowing Jesus your messenger as Christ.