Betrayed into the hands of his enemies by one of His own apostles, Jesus Christ was mocked, spat upon, scourged, crowned with thorns, sentenced to death by crucifixion, and made to carry His own cross to the place of execution. Then He was stripped, fastened to the cross by nails through His wrists and feet, and left to die by asphyxiation. All this He endured willingly for our salvation.
When Jesus died, His body and soul were separated, for that is what death means. They remained separated until the Resurrection, but His divinity remained united to both His body and His soul.
How did His death produce the effect of Redemption? Sinners had, as it were, taken from one pan of a two-pan scales--an image to represent the moral order--what they had no right to take. The Holiness of the Father, loving all that is morally right, wanted the scales of the moral order righted, wanted the debt to be paid. Further, the imbalance was infinite, so that only a divine Person incarnate could rectify it, by giving up satisfactions He could have lawfully had, and by suffering things He did not owe, with the intention of repairing the damage done to the moral order by sin. It was Christ's obedience to the Father, of infinite moral worth, which gave value to his suffering.
Pope Paul VI wrote (Constitution on Indulgences, Jan 9, 1967): "It is necessary ... for the full remission and ... reparation of sins, not only that friendship with God be reestablished... and amends be made for the offense against His wisdom and goodness, but also that all the personal as well as social values, and those of the universal order, diminished or destroyed by sin, be fully restored, ... through voluntary reparation.... Indeed Christ, 'who committed no sin,' suffered for us, 'was wounded for our iniquities, bruised for our sins.... by His bruises we are healed.' Thus there was established, as it were, a treasury of 'the infinite and inexhaustible value which the expiation and the merits of Christ our Lord have before God.'"
He willed to suffer so much also "to draw all things to Himself" (John 12:32) by proving (cf. Romans 5:8) the immense love of His Heart, which went to such lengths to make eternal happiness open to all.
Further, since as St. Paul tells us (cf. Romans 8:17), we are saved and sanctified to the extent that we are not only members of Christ, but are like Him, therefore we too must share in this work of reparation. Jesus wanted to draw us to imitate Him in His work of satisfaction.
So that we might join with Him, He commanded "Do this in memory of me." So it is precisely in the Mass that we bring our offering of whatever obedience to the Father we have carried out since the last Mass, and we present too our penance of reparation, to be joined with the obedience and reparation of Jesus and His Mother at the double consecration of bread and wine, when He Himself, using a human priest to carry out the same dramatic sign He used in the Upper Room, presents again His willingness to obey the Father, to make reparation for sin.
Taken from The Basic Catholic Catechism
PART THREE: The Apostles' Creed II - V
Fourth Article: "He suffered under Pontius Pilate, was crucified, died, and was buried"
By Rev. William G. Most. (c)Copyright 1990 by William G. Most