Catechism of the Catholic Church §2572 — excerpt
As a final stage in the purification of his faith, Abraham, "who had received the promises," is asked to sacrifice the son God had given him.
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.