Catechism of the Catholic Church §153 — excerpt
When St. Peter confessed that Jesus is the Christ, the Son of the living God, Jesus declared to him that this revelation did not come "from flesh and blood", but from "my Father who is in heaven".
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: DV 5 · DS 377 · 3010