10 Now the very essence of Religion implies Sacrifice. For the perfection ofDivine Worship is found in the submissive and reverent acknowledgment that Godis the Supreme Lord of all things, by Whose power we and all our belongingsexist. This constitutes the very nature of Sacrifice, which, on this account, isemphatically called a "thing Divine." If Sacrifices are abolished,Religion can neither exist nor be conceived. The Evangelical Law is notinferior, but superior, to the Old Law. It brings to perfection what the Old Lawhad merely begun. But the Sacrifice of the Cross was prefigured by thesacrifices of the Old Covenant long before the Birth of Jesus Christ; and afterHis Ascension, the same Sacrifice is continued by the Eucharistic Sacrifice.They greatly err, therefore, who reject this doctrine, as if it diminished thereality and efficacy of the Sacrifice which Christ offered on the Cross. He"was offered once to exhaust the sins of many" (Heb. ix., 28). Thatatonement for the sins of men was absolutely complete: nor is there any otheratonement besides that of the Cross in the Eucharistic Sacrifice. As Religionmust ever be accompanied by a sacrificial rite, it was the Divine counsel of theRedeemer that the Sacrifice of the Cross should be perpetuated. This perpetuityis in the most Holy Eucharist, which is not an empty similitude or a merecommemoration, but the very Sacrifice flows from the death of Christ: "Forfrom the rising of the sun even to the going down, my name is great among theGentiles, and in every place there is sacrifice, and there is offered to my namea clean oblation: for my name is great among the Gentiles" (Mal. i. 2).
Source: Caritatis Studium (Vatican.va)