A single day could not contain the joy of the Resurrection, so the Church extended the celebration to a season. We’re still in the midst of it.

But we who speak English suffer a fundamental disorientation when we consider this season. In most languages, the same word applies to the Jewish Passover as to the Christian feast of Jesus’ resurrection: “Pascua,” “Pascha,” “Pasqua,” “Pesach.” The English name, Easter, on the other hand, derives from an ancient German festival, about which we know very little.

Thus the term “Paschal Mystery” doesn’t have the same associations for us as it has for others. It is this mystery, according to the Catechism, which “stands at the center” of the Gospel (CCC, n. 571). All other feasts, all other mysteries point to it (CCC, n. 1171). Yet it is the same Paschal Mystery that we celebrate every Sunday and every Mass. We may think of these memorials as widening concentric circles, whose heart is the Lord’s saving passion.

For Christians, the Paschal Mystery should evoke the ancient Passover, when all the firstborn children of Israel were spared, when the chosen people were liberated from slavery, and when they embarked upon their journey to the promised land. Their deliverance began with the sacrifice of a lamb and the smearing of the lamb’s blood on the doorposts. In future generations, Jews would recall those events, but also consider them allegorically, as God’s continued deliverance of his people, out of vice and into virtue.

In the fullness of time, Jesus came as the “Lamb of God” (John 1:29). For his disciples, he was “Christ, our paschal lamb,” who “has been sacrificed” (1 Corinthians 5:7). For Christians, the Passover has not been abolished, but rather fulfilled. “Let us, therefore,” said St. Paul, “celebrate the festival … with the unleavened bread of sincerity and truth” (1 Corinthians 5:8).

Raised up in the traditions of Judaism, the first Christians could see both continuity and discontinuity from the Old Covenant to the New. They still celebrated the festival with unleavened bread, but now the sacrifice was Christ himself, who had made an offering of his body at the Last Supper. It was that paschal meal that transformed his execution into a once-for-all sacrifice.

The old Passover began with Israel’s redemption and liberation, but it culminated later with the people’s entrance into “a land flowing with milk and honey” (Joshua 5:6). Between those events, the tribes wandered for 40 years. It was a time of purification when God purged the Israelites of the lingering effects of their contact with Egyptian idolatry.

So, every year, as we prepare to celebrate Easter, we undergo purification through 40 days of Lent.

From ancient times, the Church saw the Christian pilgrimage as a movement from purification to illumination and finally to union with God. These are the stages as we pass through the sacraments of initiation. They trace a pattern that plays itself out over the course of a lifetime, a week or a year, and even over the course of a Mass.

We “pass over” from sin through penance to communion as we conform ourselves to the Easter Mysteries.