John 8:19
Then they began to say to Him, "Where is your Father?" Jesus answered, "You do not know either me or my Father. If you knew me, you would know my Father too."
John 8:54-55
Jesus answered, "If I glorify myself, such glory amounts to nothing. It is the Father who glorifies me; and you claim that He is your God.
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.
John 17:6
"I have made your very self known to the men whom you have given me out of the world. At first they were yours, but now you have given them to me, and they have obeyed your message.
Titus 1:16
They profess to know God, but by their actions they disown Him; they are detestable, disobedient, and useless for anything good.
1 John 2:3-4
By this we can be sure that we know Him -- if we practice obedience to His commands.