For Our Sins
From the Catechism of the Catholic Church, Simplified
Jesus Embraced Plan of Salvation (606-607)
Christ always embraced the Father's will. "My food is to do the will of him who sent me, and to accomplish his work" (Jn 4:34). His death was in loving union with the Father. "The Father loves me, because I lay down my life" (Jn 10:17).
Jesus accepted the Father's plan of redemption. Foreseeing his death, Jesus said, "For this purpose I have come to this hour" (Jn 12:27). From the cross he said, "It is finished" (Jn 19:30).
The Suffering Lamb (608-609)
Jesus is the "Lamb of God who takes away the sin of the world" (Jn 1:29). Jesus is the Suffering Servant. He is the new Paschal Lamb allowing himself to be led to slaughter. Jesus came "to give his life as a ransom for many" (Mk 10:45). Jesus was totally free in this decision. "I lay it down of my own accord" (Jn 10:18).
Perpetuating His Sacrifice (610-611)
"On the night he was betrayed," Jesus transformed the Last Supper into a memorial of his voluntary offering to the Father. He spoke of his body "given for you" and of his blood already being "poured out for the forgiveness of sins" (Lk 22:19). Jesus told his apostles to perpetuate this memorial of his sacrifice. In doing so, he made them priests of the New Covenant.
Accepting the Cup (612)
In Gethsemane, Jesus accepted this cup of the New Covenant from his Father. He was "obedient even to death," saying "not as I will but as you will" (Mt 26:39). Although the human nature was assumed by the "Author of life," Jesus accepted death as part of our redemption.
Surpassing All Other Sacrifices (613-615)
Christ's death accomplishes man's redemption and restores man to God through the blood of the Covenant (Mt 26:28). Christ's unique sacrifice completes and surpasses all other sacrifices. It is a gift from the Father (who handed over his Son) and a gift from the Son (who freely accepted death).
As prophesied by Isaiah, Jesus actually substituted himself for us. As the Suffering Servant, he bore "the sin of many" so the many would "be accounted righteous" (Isa 53:10-12).
Becoming the Source of Salvation (616-617)
Jesus gave the value of redemption and atonement to his sacrifice. Not even the holiest man can take upon himself the sins of others and offer himself as a sacrifice. However, because the divine person of the Son exists in Christ, this sacrifice is a redemption for all. Christ's sacrifice was unique. Jesus is "the source of eternal salvation" and "merited justification for us" (Council of Trent).
Invited to Drink His Cup (618)
Christ can make us partners in his death in a way known only to God. He invites all to "take up their cross and follow him" (Mt 16:24). James and John were invited to drink the same cup (Mk 10:39) and Mary, his mother, was intimately involved in the cross. "Apart from the cross there is no other ladder by which we may get to heaven" (St. Rose of Lima).