Catechism of the Catholic Church §1727 — excerpt
The beatitude of eternal life is a gratuitous gift of God. It is supernatural, as is the grace that leads us there.
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.