Necessity and Purpose of the Resurrection
from The Roman Catechism
It was necessary that Jesus should rise again in order to manifest the justice of God. For it was most fitting that He who was degraded and loathed with ignominy through obedience to God, should have been exalted by God. The Apostle gives this reason in his Epistle to the Philippians: "He humbled Himself and became obedient unto death, even death on a cross. Therefore God has highly exalted Him" (Ph 2:8-9).
Furthermore, he rose with the purpose of confirming our faith, which is necessary for our justification. For the resurrection of Christ from the dead by his own power gives our faith its principal argument for his divinity.
[At the same time as it proves Christ's divinity, the Resurrection also shows us that the sacrifice of Christ was acceptable to the Father, and serves a sign of the ratification of the New Covenant. Thus:]
It also nurtures and sustains our hope, for, as Christ rose again, we are established in the certain hope that we too shall rise again. The members must necessarily arrive at the condition of their head. This is the conclusion which St. Paul draws from the reasoning which he uses in his Epistles to the Corinthians and Thessalonians (see 1 Cor 15:12; 1 Th 4:14). And Peter, the Prince of the Apostles, says: "Blessed be God the Father of our Lord Jesus Christ! By His great mercy we have been born anew to a living hope through the resurrection of Jesus Christ from the dead" (1 Pt 1:3).
Finally, the resurrection of our Lord was necessary to complete the mystery of our salvation and redemption. For Christ liberated us from the slavery of sin by His death and restored to us through his resurrection the most important privileges which we had lost by sin. Hence the Apostle Paul teaches: "Jesus was to put the death for our trespasses and raised for our justification" (Rm 4:25).
Therefore, so that nothing be wanting to perfect the work of our salvation, it was necessary that, as he died, he should also rise again from the dead.
From The Roman Catechism ("Catechism of the Council of Trent"), translated by Robert I. Bradley, S.J., and Rev. Msgr. Eugene Kevane.