2nd Sunday in Ordinary Time, Year A. John 1:29-34.
AIM: To explain the doctrine of eucharistic sacrifice.
ABehold, the Lamb of God!@ John=s words from the opening of the gospel reading we have just heard are so familiar to us that we don=t stop to ask what they mean. We hear the words immediately before Communion at every Mass, when the priest, holds up the Lord=s body and says: AThis is the Lamb of God, who takes away the sin of the world.@ What do those words really mean?
To understand them we must plunge into the distant history of Jesus= people and read about their greatest feast: the Passover. Here is the account from the book of Exodus, chapter 12:
Moses told the people, AGo and get a lamb for your families and slaughter it for the Passover. Then take some of the hyssop, dip it in the blood [of the lamb] and smear some of the blood ... on the door-posts and lintel. ... The Lord will go through
and strike it, but when he
sees the blood on the lintel and doorposts, he will pass over that door
and will not let the destroyer enter your houses to strike you. You shall keep
this as a rule of all time. When your children ask you, >What is the meaning of this rite?= you shall say: >It is the Lord=s Passover, for he passed over
the houses of the Israelites in Egypt
when he struck the Egyptians, but spared our houses. (Ex. 12: 21-27) Egypt
The blood of the Passover lamb smeared on the doorposts kept the people safe. Later the lamb was thought of as sacrificed to God: a gift through which God and his human worshipers were reconciled. Such gifts, offered in sacrifice to God, were supposed to restore the fellowship which had been broken by human sin.
The prophets of Jesus= people criticized these sacrificial offerings. They were based, the prophets pointed out, on the fiction that the things offered to God represented those who offered them. What God really wants, the prophets said, is not things (since everything belongs to him already). God wants men and women themselves. But how could people really offer themselves to God in sacrifice? And to the extent that people did offer themselves in a spiritual sense, they were offering God gifts stained by sin. Hence the whole sacrificial system failed to achieve what it was meant to achieve. This a central theme of the Letter to the Hebrews:
Every priest [and the writer is talking about Jewish priests] stands performing his daily service and offering time after time the same sacrifices which can never take away sins. (Heb. 10:11)
Hebrews also affirms, however, that a perfect, unblemished sacrifice has been offered. The fellowship between sinful humanity and God has been restored. (Cf. Heb. 10:12). Jesus is the priest who offers, and Jesus is himself the sacrifice offered. His life of perfect obedience to his heavenly Father, consummated on
Atakes away the sin of the world,@ as John says at the beginning of
today=s gospel. As the blood of the
Passover lamb protected Jesus= ancestors, so his blood protects us, his spiritual
descendants. Because of our sins we are unworthy to stand before God, to pray
to him, to claim his blessing. But as sisters and brothers of Jesus Christ we can
do all these things.
Jesus= sacrifice, which mends the fellowship between us and God, broken by our sins, is not just long ago and far away. Though the Last Supper and
unrepeatable, they become, here and now, a living reality each time we
obey Jesus command at the Last Supper, to Ado this in memory of me@ with the bread and wine. To this day
part of the Jewish Passover ritual is the child=s question: AWhat is the meaning of this rite?@ To which the person presiding
replies: AIt is the Lord=s Passover.@ The unique past event is not
repeated. But through its ritual celebration it becomes a living reality for
the worshipers today.
This is what we Catholics believe about the
At the Last
Supper, celebrated in the context of a Jewish Passover meal, Jesus took bread
and said: AThis is my body.@ He meant: >This is me. When you do this I am
truly with you. I give myself to you.= Saying over the cup, AThis is my blood,@ Jesus was telling us: >I am the one whose poured out blood
keeps you safe, and brings you into a new relationship with God.= The bread and cup of this meal,
previously a celebration of the Passover, are now a pledge of Jesus= personal presence with us, his
friends. That is the meaning of the
offertory prayer we shall hear in a few moments: AWhen we proclaim the death of the
Lord, you continue the work of his redemption.@ Mass.
The Catechism says: AThe Eucharist is the memorial of Christ=s Passover, the making present and the sacramental offering of his unique sacrifice ...  The memorial is not merely the recollection of past events but the proclamation of the mighty works wrought by God for men. In the liturgical celebration of these events, they become in a certain way present and real. ...  The Eucharist is thus a sacrifice because it re-presents (makes present) the sacrifice of the cross, because it is its memorial and because it applies its fruit.@ 
The Mass is not a repetition of the Last Supper and Calvary. It is, in a unique and specially intense way, their sacramental commemoration. It makes present, spiritually but truly, what it commemorates. When we Ado this@ with the bread and wine, as Jesus commanded, we are there! We are with the friends of Jesus in the upper room; with Mary and the Beloved Disciple at the cross. Here in the sacrifice of the Mass we encounter him who is the true Lamb of God: the one who destroys sin; who protects us through his poured-out blood from sin=s just penalty; the one through whom we can approach God, not in fear and trembling because of our sins, but in confidence and love; calling him, as Jesus taught us to do: AFather.@
So much meaning, so much wonder, so much drama! How often do we recognize it, and truly worship?