John 3:3-7

Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.

Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?

Jesus answered, 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.

That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.

Marvel not that I said unto thee, Ye must be born again.

1 Corinthians 15:1-4

15 Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;

By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.

For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;

And that he was buried, and that he rose again the third day according to the scriptures: