Catechism of the Catholic Church §158 — excerpt
"Faith seeks understanding": it is intrinsic to faith that a believer desires to know better the One in whom he has put his faith, and to understand better what He has revealed; a more penetrating knowledge will in turn call forth a greater faith, increasingly set afire by love.
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. Anselm, Prosl. prooem. PL 153 225A · DV 5 · St. Augustine, Sermo 43, 7, 9: PL 38, 257-258