Catechism of the Catholic Church §856 — excerpt
The missionary task implies a respectful dialogue with those who do not yet accept the Gospel. Believers can profit from this dialogue by learning to appreciate better "those elements of truth and grace which are found among peoples, and which are, as it were, a secret presence of God."
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: RMiss 55 · AG 9