Jesus said

Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. John 3:3

Verily, verily, I say unto thee, Except a man be born of water and [of] the Spirit, he cannot enter into the kingdom of God. John 3:5

That which is born of the flesh is flesh; and that which is born of the Spirit is spirit. John 3:6

Marvel not that I said unto thee, Ye must be born again. John 3:7

The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit. John 3:8

Art thou a master of Israel, and knowest not these things? John 3:10

Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness. John 3:11

If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you [of] heavenly things? John 3: 12

And no man hath ascended up to heaven, but he that came down from heaven, [even] the Son of man which is in heaven. John 3:13

And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up: John 3:14

That whosoever believeth in him should not perish, but have eternal life. John 3: 15

For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.

John 3: 16

For God sent not his Son into the world to condemn the world; but that the world through him might be saved. John 3: 17

He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God. John 3:18