Easter is the greatest feast in the Christian calendar. On this Sunday, Christians celebrate the resurrection of Jesus Christ from the dead. For Catholics, Easter Sunday comes at the end of 40 days of prayer, fasting, and almsgiving known as Lent. Through spiritual struggle and self-denial, we have prepared ourselves to die spiritually with Christ on Good Friday, the day of His Crucifixion, so that we can rise again with Him in new life on Easter.

Because of the central importance of Easter to the Christian faith, the Catholic Church requires that all Catholics who have made their First Communion receive the Holy Eucharist sometime during the Easter season, which lasts through Pentecost, 50 days after Easter. (The Church also urges us to take part in the Sacrament of Confession before receiving this Easter communion.) This reception of the Eucharist is a visible sign of our faith and our participation in the Kingdom of God. Of course, we should receive Communion as frequently as possible; this “Easter Duty” is simply the minimum requirement set by the Church.

Communion – Our Easter Duty:
Because of the central importance of Easter to the Christian faith, the Catholic Church requires that all Catholics who have made their First Communion receive the Holy Eucharist sometime during the Easter season, which lasts through Pentecost, 50 days after Easter. (The Church also urges us to take part in the Sacrament of Confession before receiving this Easter communion.) This reception of the Eucharist is a visible sign of our faith and our participation in the Kingdom of God. Of course, we should receive Communion as frequently as possible; this “Easter Duty” is simply the minimum requirement set by the Church.

New Life in Christ:
That is why people who are converting to Catholicism traditionally are baptized at the Easter Vigil service, which takes place on Holy Saturday (the day before Easter), starting sometime after sunset. They have usually undergone a long process of study and preparation known as the Rite of Christian Initiation for Adults (RCIA). Their baptism parallels Christ’s own Death and Resurrection, as they die to sin and rise to new life in the Kingdom of God.

The Fulfillment of Our Faith:
Easter is a day of celebration because it represents the fulfillment of our faith as Christians. St. Paul wrote that, unless Christ rose from the dead, our faith is in vain (1 Corinthians 15:17). Through his death, Christ saved mankind from bondage to sin, and He destroyed the hold that death has on all of us; but it is His Resurrection that gives us the promise of new life, both in this world and the next.

The Coming of the Kingdom:
That new life began on Easter Sunday. In the Our Father, we pray that “Thy Kingdom come, on earth as it is in Heaven.” And Christ told His disciples that some of them would not die until they saw the Kingdom of God “coming in power” (Mark 9:1). The early Christian Fathers saw Easter as the fulfillment of that promise. With the resurrection of Christ, God’s Kingdom is established on earth, in the form of the Church.

Theological significance
A stained glass window depicting the Passover Lamb, a concept integral to the foundation of Easter[21][27] The New Testament teaches that the resurrection of Jesus, which Easter celebrates, is a foundation of the Christian faith.[28] The resurrection established Jesus as the powerful Son of God and is cited as proof that God will judge the world in righteousness.[29] God has given Christians “a new birth into a living hope through the resurrection of Jesus Christ from the dead”.[30] Christians, through faith in the working of God are spiritually resurrected with Jesus so that they may walk in a new way of life.[29]

Easter is linked to the Passover and Exodus from Egypt recorded in the Old Testament through the Last Supper and crucifixion that preceded the resurrection.[21] According to the New Testament, Jesus gave the Passover meal a new meaning, as he prepared himself and his disciples for his death in the upper room during the Last Supper.[21] He identified the matzah and cup of wine as his body soon to be sacrificed and his blood soon to be shed. Paul states, “Get rid of the old yeast that you may be a new batch without yeast—as you really are. For Christ, our Passover lamb, has been sacrificed”;[31] this refers to the Passover requirement to have no yeast in the house and to the allegory of Jesus as the Paschal lamb.[32]

One interpretation of the Gospel of John is that Jesus, as the Passover lamb, was crucified at roughly the same time as the Passover lambs were being slain in the temple, on the afternoon of Nisan 14.[33] The scriptural instructions specify that the lamb is to be slain “between the two evenings”, that is, at twilight. By the Roman period, however, the sacrifices were performed in the mid-afternoon. Josephus, Jewish War 6.10.1/423 (“They sacrifice from the ninth to the eleventh hour”). Philo, Special Laws 2.27/145 (“Many myriads of victims from noon till eventide are offered by the whole people”). This interpretation, however, is inconsistent with the chronology in the Synoptic Gospels. It assumes that text literally translated “the preparation of the passover” in John 19:14 refers to Nisan 14 (Preparation Day for the Passover) and not necessarily to Yom Shishi (Friday, Preparation Day for Sabbath)[34][35][36][37] and that the priests’ desire to be ritually pure in order to “eat the passover”[38] refers to eating the Passover lamb, not to the public offerings made during the days of Unleavened Bread.[39]

In the Early Church
The first Christians, Jewish and Gentile, were certainly aware of the Hebrew calendar,[nb 6] but there is no direct evidence that they celebrated any specifically Christian annual festivals.[40] Christians of Jewish origin were the first to celebrate the resurrection of Jesus. Since the date of the resurrection was close the timing of Passover, they likely celebrated the resurrection as a new facet of the Passover festival.[18] Direct evidence for the Easter festival begins to appear in the mid-second century. Perhaps the earliest extant primary source referencing Easter is a mid-second-century Paschal homily attributed to Melito of Sardis, which characterizes the celebration as a well-established one.[40] Evidence for another kind of annual Christian festival, the commemoration of martyrs, begins to appear at about the same time as evidence for the celebration of Easter.[41] But while martyrs’ days (usually the individual dates of martyrdom) were celebrated on fixed dates in the local solar calendar, the date of Easter was fixed by means of the local Jewish lunisolar calendar. This is consistent with the celebration of Easter having entered Christianity during its earliest, Jewish period, but does not leave the question free of doubt.[42]

The ecclesiastical historian Socrates Scholasticus attributes the observance of Easter by the church to the perpetuation of its custom, “just as many other customs have been established,” stating that neither Jesus nor his Apostles enjoined the keeping of this or any other festival. Although he describes the details of the Easter celebration as deriving from local custom, he insists the feast itself is universally observed.[43]

Date
Easter and the holidays that are related to it are moveable feasts, in that they do not fall on a fixed date in the Gregorian or Julian calendars (both of which follow the cycle of the sun and the seasons). Instead, the date for Easter is determined on a lunisolar calendar similar to the Hebrew calendar. The First Council of Nicaea (325) established the date of Easter as the first Sunday after the full moon (the Paschal Full Moon) following the March equinox. Ecclesiastically, the equinox is reckoned to be on 21 March (even though the equinox occurs, astronomically speaking, on 20 March in most years), and the “full moon” is not necessarily the astronomically correct date.
In Western Christianity, using the Gregorian calendar, Easter always falls on a Sunday between March 22 and April 25 inclusive, within about seven days after the astronomical full moon.[44] The following day, Easter Monday, is a legal holiday in many countries with predominantly Christian traditions.

Eastern Christianity bases its calculations on the Julian Calendar. Because of the 13-day difference between the calendars between 1900 and 2099, 21 March corresponds, during the 21st century, to 3 April in the Gregorian Calendar. Easter therefore varies between 4 April and 8 May on the Gregorian calendar (the Julian calendar is no longer used as the civil calendar of the countries where Eastern Christian traditions predominate). Also, because the Julian “full moon” is always several days after the astronomical full moon, the eastern Easter is often later, relative to the visible moon’s phases, than western Easter.

Among the Oriental Orthodox some churches have changed from the Julian to the Gregorian calendar and the date for Easter as for other fixed and moveable feasts is the same as in the Western church.[45]