John 17:3 And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.
1 John 2:3-5 Now by this we know that we know Him, if we keep His commandments. He who says, "I know Him," and does not keep His commandments, is a liar, and the truth is not in him. But whoever keeps His word, truly the love of God is perfected in him. By this we know that we are in Him.
Luke 1:34 Then Mary said to the angel, "How can this be, since I do not know a man?"
John 8:32 And you shall know the truth, and the truth shall make you free."