Catechism of the Catholic Church §1570 — excerpt
Deacons share in Christ's mission and grace in a special way. The sacrament of Holy Orders marks them with an imprint (“character") which cannot be removed and which configures them to Christ, who made himself the "deacon" or servant of all.
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: LG 41 · AA 16 · St. Polycarp, Ad Phil. 5, 2: SCh 10, 182 · LG 29 · SC 35 # 4 · AG 16