Catechism of the Catholic Church §1622 — excerpt
"Inasmuch as it is a sacramental action of sanctification, the liturgical celebration of marriage . . must be, per se, valid, worthy, and fruitful." It is therefore appropriate for the bride and groom to prepare themselves for the celebration of their marriage by receiving the sacrament of penance.
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: FC 67