CCC 1544
© Libreria Editrice Vaticana Source: vatican.va
Everything that the priesthood of the Old Covenant prefigured finds its fulfillment in Christ Jesus, the "one mediator between God and men." 2 Tim 2:5. The Christian tradition considers Melchizedek, "priest of God Most High," as a prefiguration of the priesthood of Christ, the unique "high priest after the order of Melchizedek"; Heb 5:10; cf. 6:20; Gen 14:18. "holy, blameless, unstained," Heb 7:26. "by a single offering he has perfected for all time those who are sanctified," Heb 10:14. that is, by the unique sacrifice of the cross.
Read the full chapter 3. The Sacraments at the Service of Communion ¶1533–1666