CCC 1295

By this anointing the confirmand receives the "mark," the seal of the Holy Spirit. A seal is a symbol of a person, a sign of personal authority, or ownership of an object. Cf Gen 38:18; 41:42; Deut 32:34; CT 8:6. Hence soldiers were marked with their leader's seal and slaves with their master's. A seal authenticates a juridical act or document and occasionally makes it secret. Cf. 1 Kings 21:8; Jer 32:10; Isa 29:11.

Read the full chapter 1. The Sacraments of Christian Initiation ¶1212–1419