Catechism of the Catholic Church §1718 — excerpt
The Beatitudes respond to the natural desire for happiness. This desire is of divine origin: God has placed it in the human heart in order to draw man to the One who alone can fulfill it:
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: St. Augustine, De moribus eccl. 1, 3, 4: PL 32,1312 · St. Augustine, Conf. 10, 20: PL 32, 791 · St. Thomas Aquinas, Expos. in symb. apost. I