John 3:1-8

Now there was a man of the Pharisees, named Nicodemus, a ruler of the Jews; This man came to Him by night, and said to Him, 'Rabbi, we know that You have come from God as a teacher; for no one can do these signs that You do unless God is with him'. Jesus answered and said to him, 'Truly, truly, I say to you, unless one is born again, he cannot see the kingdom of God.' Nicodemus said to Him, 'How can a man be born when he is old? He cannot enter a second time into his mother's womb and be born, can he?' Jesus answered, 'Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter into the kingdom of God. 'That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. 'Do not marvel that I said to you, 'You must be born again.' 'The wind blows where it wishes and you hear the sound of it, but do not know where it comes from and where it is going; so is everyone who is born of the Spirit.

John 6:63

It is the Spirit who gives life; the flesh profits nothing; the words that I have spoken to you are spirit and are life.

Titus3.5

He saved us, not on the basis of deeds which we have done in righteousness, but according to His mercy, by the washing of regeneration and renewing by the Holy Spirit