The Catechism in Questions & Answers

528. What do we mean by the “rebirth out of water and the Spirit”?

The two sacraments of Holy Baptism with water and Holy Sealing together comprise the “rebirth out of water and the Spirit”. Through these sacraments, God creates a “new creation”—life from God.

“Jesus answered, ‘Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God’.”
John 3: 5
“Therefore, if anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new.”
2 Corinthians 5: 17