Pascha (or Paskha)  is the fundamental and most important festival of the Eastern and Oriental Orthodox Churches. Every other religious festival on their calendars, including Christmas, is secondary in importance to the celebration of the Resurrection of Jesus Christ. This is reflected in rich Paschal customs in the cultures of countries that have traditionally had an Orthodox Christian majority. Eastern Catholics have similar emphasis in their calendars, and many of their liturgical customs are very similar. This is not to say that Christmas and other elements of the Christian liturgical calendar are ignored. Instead, these events are all seen as necessary but preliminary to, and illuminated by, the full climax of the Resurrection, in which all that has come before reaches fulfilment and fruition. They shine only in the light of the Resurrection. Pascha (Easter) is the primary act that fulfils the purpose of Christ's ministry on earth—to defeat death by dying and to purify and exalt humanity by voluntarily assuming and overcoming human frailty. This is succinctly summarized by the Paschal troparion, sung repeatedly during Pascha until the Apodosis of Pascha, which is the day before Ascension:

Christ is risen from the dead, Trampling down death by death, And upon those in the tombs Bestowing life!

Христос воскресе из мертвых, Cмертию смерть поправ, И сущим во гробех Живот даровав.