Catechism of the Catholic Church §2779 — excerpt
Before we make our own this first exclamation of the Lord's Prayer, we must humbly cleanse our hearts of certain false images drawn "from this world."
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: Tertullian De orat. 3: PL 1, 1155