Catechism of the Catholic Church

The altar, around which the Church is gathered in the celebration of the Eucharist, represents the two aspects of the same mystery: the altar of the sacrifice and the table of the Lord. This is all the more so since the Christian altar is the symbol of Christ himself, present in the midst of the assembly of his faithful, both as the victim offered for our reconciliation and as food from heaven who is giving himself to us. "For what is the altar of Christ if not the image of the Body of Christ?" asks St. Ambrose. He says elsewhere, "The altar represents the body [of Christ] and the Body of Christ is on the altar." The liturgy expresses this unity of sacrifice and communion in many prayers. Thus the Roman Church prays in its anaphora: (1182) > We entreat you, almighty God, that by the hands of your holy Angel this offering may be borne to your altar in heaven in the sight of your divine majesty, so that as we receive in communion at this altar the most holy Body and Blood of your Son, we may be filled with every heavenly blessing and grace.