You mentioned that the Mass is “rooted in Old Testament tradition.” What Old Testament tradition was Jesus celebrating at the Last Supper?
March 8, 2020, 12:00 PM

At the Last Supper, Jesus was celebrating the Passover.

Sacrificial offerings made as an expression of worship can be seen throughout the Old Testament. The high point of Jewish worship, though, was (and remains) the Passover. The Passover commemorated how the Jewish people were set free from slavery in Egypt by the sacrifice of an unblemished lamb (see Ex 12:5). For those households who, in obedience to God (speaking through Moses), sacrificed a lamb, put its blood on their door, and ate its flesh, the angel of death “passed over” their homes and the lives of their firstborn sons were spared. In all other homes the firstborn son died. After this act of God, the Pharaoh released the Hebrews from slavery. Thus, the Passover sacrifice recalls how God led His people out of Egypt into freedom. As prescribed in the twelfth chapter of Exodus, the Jewish people were to sacrifice a lamb and eat it with unleavened bread as an offering to God in thanksgiving for what He had done and to commemorate this event every year.

At the Last Supper, as He was celebrating the Passover with His apostles, Jesus elevated and fulfilled the Old Testament tradition by “reveal[ing] that He himself is the true sacrificial lamb, destined in the Father’s plan from the foundation of the world.: When He offered the unleavened bread and said to His apostles “this is my body,” Jesus became the new Passover Lamb, the “Lamb of God” (see Jn 1:29), setting His people free from slavery to sin and death, and making them God’s own children. As God promised, the sacrificial worship of Passover is fulfilled and continues to the end of time in the “perpetual institution” of the Mass (see Ex 12:14).