In Genesis, the people of God included bread and wine in their sacrifice as a sign of gratitude to God. The priest-king Melchizedek of Salem “brought out bread and wine” as offerings to the Most High.
In Exodus, God told the people to eat unleavened bread to commemorate the haste of their departure from oppression. The wine at the end of the Passover meal was a sign of joy and hope.
Then Jesus came and revealed the full meaning of the bread and wine in the Last Supper.
“This is my body which is given for you. Do this in remembrance of me…This cup which is poured out for you is the New Covenant in my blood.” (Luke 22: 19-20). The consecrated bread and wine are literally the Body and Blood of Jesus Christ.
At the Mass we renew in an unbloody way the bloody sacrifice of 2000 years ago.
We offer God to God, we present Jesus Christ to the Father. At Calvary Jesus offered Himself, the crushed soul, the broken body, the precious blood. The Eucharist makes present that Sacrifice: the same body is broken, the same blood is shed.
“The same Christ who offered himself once in a bloody manner on the altar of the cross is contained and is offered in an unbloody manner,” teaches the Catechism of the Catholic Church paragraph 1367.
When the priest breaks the host, this act symbolizes the breaking of the body of Jesus in the cross.
The holy sacrifice of the Mass unleashes the same torrent of grace for us in the present age. Indeed, the flood of grace is so intense that at Mass we are forgiven our venial sins. The blood is “poured out for many for the forgiveness of sins” (Matthew 26:28).
The Catechism indeed affirms that Holy Communion “wipes away venial sins” and also “preserves us from future mortal sins.”
No wonder then that the Catechism describes the Eucharist as the pledge of our future glory.