The festival of the Resurrection of the Lord (or Easter Sunday) is the center of the Christian year. On this occasion the church joyfully proclaims the good news that is at the very heart of the gospel: that Jesus Christ is risen from the dead.
It is sometimes said that every Sunday is a little Easter; liturgical theologian Laurence Stookey suggests that it might be more appropriate to say that every Easter is a great Sunday (Calendar: Christ’s Time for the Church, Abingdon Press, 1996, 158-161). Easter Sunday is the Lord’s Day writ large: a great annual celebration of Christ’s resurrection on the first day of the week. As such, the service should be centered around the typical and fundamental elements of Christian worship on the Lord’s Day: the proclamation of the Word and the celebration of the Lord’s Supper. Easter Sunday is also an especially appropriate time for the sacrament of Baptism, if not celebrated during the Easter Vigil of the previous night.
Easter Sunday is something like the keystone of an arch — the top and center stone upon which all the other stones lean and depend — both in terms of its theological significance and its relation to other events in the Christian year. Theologically speaking, the faith we claim and the life we live depend on the affirmation, celebration and proclamation of Christ’s resurrection. In a chronological sense — since Easter is a “moveable feast,” taking place on a different date each year — all the other events of the Christian year (from the Transfiguration of the Lord and Ash Wednesday through Pentecost and Trinity Sunday) pivot around the date of Easter Sunday, shifting accordingly.
For Western Christians (Catholics and Protestants) the date of Easter is the first Sunday that comes after the first full moon that occurs on or after March 21 (the Spring Equinox) — occasionally shifted to the following Sunday, when the original date happens to coincide with the Jewish Passover. This computation means that Easter always occurs sometime between March 22 and April 25, inclusive. The Eastern Churches (Greek and Russian Orthodox, e.g.) use a different set of astronomical tables based on the Julian Calendar (instead of the Gregorian), which means that Orthodox Easter generally follows the Western date by one, four, or five weeks (sometimes occurring in early May).
An excerpt from the Companion to the Book of Common Worship (Geneva Press, 2003, 107-108)
Pascha [or Easter] is the central event, the time of transformation, of becoming a resurrected people, God’s new people. On this Sunday of all Sundays, Pascha, we celebrate our transformation as a new people. When Christ rose from the grave, death and all other “principalities and powers” that seek to entomb God’s will were forever defeated.
Easter is not simply the miracle of a dead person raised from the grave, but a celebration of power that can shatter death in order that people can freely serve the God of life. In the resurrection of Christ, God’s awesome purposes were on display, revealing a radically new world of peace and harmony and equality and mutuality, about which we can only dream. The Lord of the future has been disclosed to us. Both the incarnation at Christmas and the resurrection at Easter testify to the lordship of Christ. …
On Easter we glimpse a new landscape — the age to come — and experience a sense of holy awe at the significance of the resurrection for human life. The shape of the age to come reveals a new people of God, a new humanity.
When Christ was crucified, humanity died with him on Calvary. But on Easter morning, a new world was born — raised up with the crucified and risen Christ. Bursting the bonds of death, the first human being of a new human race, Jesus Christ, appeared among those who crucified him. In the midst of the old sin-struck world, God gave the world a new beginning, a new humanity. By faith the old guilt-ridden humanity was born again into the new forgiven humanity of Jesus Christ. Ever since, here and there, clusters of the new people of God live according to the new social order of the new age.
Therefore, Easter faith recalls the past, especially the awesome act of God in raising the crucified Christ from the grave. Easter hope looks to the promised future, to that which awaits us. Easter love celebrates the presence of the crucified and risen Christ who is now among us, reconciling us as one people. Resurrection faith asserts that by grace we are born again into the new humanity of Jesus Christ. We are called to new life for God and for neighbors. As representatives of the new humanity we walk in newness of life.