Catechism of the Catholic Church §2785 — excerpt
Second, a humble and trusting heart that enables us "to turn and become like children": for it is to "little children" that the Father is revealed.
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. John Cassian, Coll. 9, 18 PL 49, 788c · St. Augustine, De serm. Dom. in monte 2, 4, 16: PL 34, 1276