Ephesians 1:17-18 KJV

17 That the God of our Lord Jesus Christ, the Father of glory, may give unto you the spirit of wisdom and revelation in the knowledge of him:
18 The eyes of your understanding being enlightened; that ye may know what is the hope of his calling, and what the riches of the glory of his inheritance in the saints,

John 17:3 KJV

3 And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent.

1 John 5:20 AMPC

20 And we [have seen and] know [positively] that the Son of God has [actually] come to this world and has given us understanding and insight [progressively] to perceive (recognize) and come to know better and more clearly Him Who is true; and we are in Him Who is true—in His Son Jesus Christ (the Messiah). This [Man] is the true God and Life eternal.