Easter Vigil in the context of "Alleluia"

Church membership, in Christianity, is the state of belonging to a local church congregation, which in most cases, simultaneously makes one a member of a Christian denomination and the universal Christian Church. Christian theologians have taught that church membership is commanded in the Bible. The process of becoming a church member varies based on the Christian denomination. Those preparing to become full members of a church are known variously as catechumens, candidates or probationers depending on the Christian denomination and the sacramental status of the individual.

Lent (Latin: Quadragesima, 'Fortieth') is the solemn Christian religious observance in the liturgical year in preparation for Easter. It echoes the 40 days Jesus spent fasting in the desert and enduring temptation by Satan, according to the Gospels of Matthew, Mark and Luke, before beginning his public ministry. Lent is usually observed in the Catholic, Lutheran, Moravian, Anglican, United Protestant and Orthodox Christian traditions, among others. A number of Anabaptist, Baptist, Methodist, Reformed (including certain Continental Reformed, Presbyterian and Congregationalist churches), and nondenominational Christian churches also observe Lent, although many churches in these traditions do not.

Which days are enumerated as being part of Lent differs between denominations (see below), although in all of them Lent is described as lasting for a total duration of 40 days, the number of days Jesus, as well as Moses and Elijah, went without food in their respective fasts. In Lent-observing Western Christian denominations, Lent begins on Ash Wednesday and ends approximately six weeks later; depending on the Christian denomination and local custom, Lent concludes either on the evening of Maundy Thursday (Holy Thursday), or at sundown on Holy Saturday when the Easter Vigil is celebrated, though in either case, Lenten fasting observances are maintained until the evening of Holy Saturday. Sundays may or may not be excluded, depending on the denomination. In Eastern Christianity – including Eastern Orthodox, Eastern Catholics, Eastern Lutherans, and Oriental Orthodox – Great Lent is observed continuously without interruption for 40 days starting on Clean Monday and ending on Lazarus Saturday before Holy Week.

Holy Saturday (Latin: Sabbatum Sanctum), also known as Great and Holy Saturday, Low Saturday, the Great Sabbath, Hallelujah Saturday, Saturday of the Glory, Easter Eve, Joyous Saturday, the Saturday of Light, Good Saturday, or Black Saturday, among other names, is the final day of Holy Week, between Good Friday and Easter Sunday, and when Christians prepare for the Christian feast of Easter.

The day commemorates the Harrowing of Hell while Jesus Christ's body lay in the tomb. Christians of the Catholic, Lutheran, and Anglican denominations begin the celebration of the Easter Vigil service on Holy Saturday, which provides a transition to the season of Eastertide; in the Moravian Christian tradition, graves are decorated with flowers during the day of Holy Saturday and the celebration of the sunrise service starts before dawn on Easter Sunday. Congregations of the Reformed and Methodist denominations may hold either the Easter Vigil or an Easter Sunday sunrise service.

The Paschal Triduum or Easter Triduum (Latin: Triduum Paschale), Holy Triduum (Latin: Triduum Sacrum), or the Three Days, is the Christian period of three days that begins with the liturgy on the evening of Maundy Thursday, reaches its high point in the Easter Vigil, and closes with evening prayer on Easter Sunday. It is a moveable observance recalling the Passion, Crucifixion, Death, burial, and Resurrection of Jesus, as portrayed in the canonical Gospels.

In the Anglican, Lutheran, Methodist, Moravian and Reformed traditions, the Paschal Triduum straddles the two liturgical seasons of Lent and Easter in the Church calendar (Holy Saturday is the last day of Lent, with the Easter Vigil being the first liturgy of Eastertide). In the Roman Catholic tradition since the 1955 reform by Pope Pius XII, the Easter Triduum has been more clearly distinguished as a separate liturgical period.

In Christian liturgy, a vigil is, in origin, a religious service held during the night leading to a Sunday or other feastday. The Latin term vigilia, from which the word is derived meant a watch night, not necessarily in a military context, and generally reckoned as a fourth part of the night from sunset to sunrise. The four watches or vigils were of varying length in line with the seasonal variation of the length of the night.

During the Liturgy of the Eucharist, the second part of the Mass, the elements of bread and wine are considered to have been changed into the veritable Body and Blood of Jesus Christ. The manner in which this occurs is referred to by the term transubstantiation, a theory of St. Thomas Aquinas, in the Roman Catholic Church. Members of the Orthodox, Anglican, and Lutheran communions also believe that Jesus Christ is really and truly present in the bread and wine, but they believe that the way in which this occurs must forever remain a sacred mystery. In many Christian churches, some portion of the consecrated elements is set aside and reserved after the reception of Communion and referred to as the reserved sacrament. The reserved sacrament is usually stored in a tabernacle, a locked cabinet made of precious materials and usually located on, above, or near the high altar. In Western Christianity usually only the Host, from Latin: hostia, meaning "victim" (the consecrated bread), is reserved, except where wine might be kept for the sick who cannot consume a host.

The reasons for the reservation of the sacrament vary by tradition, but until around 1000 AD the only reason for reserving the sacrament was to be taken to the ill, homebound, or dying (viaticum). After that devotional practices arose, as for Eucharistic adoration and for Communion services when a priest is unavailable to celebrate the Eucharist. During the Paschal Triduum, the sacrament is taken in procession from the tabernacle, if on the high altar or otherwise in the sanctuary, to the Altar of Repose, and reserved from the end of the Mass of the Lord's Supper until the Communion Rite on Good Friday (called the Mass of the Presanctified, since the Eucharistic Prayer and consecration are omitted in the Good Friday celebration); this period is seen by some as symbolic of the time between the Last Supper and the Crucifixion of Jesus. The Blessed Sacrament is then absent from the tabernacle until the end of the Easter Vigil.

The Litany of the Saints (Latin: Litaniae Sanctorum) is a formal prayer of the Roman Catholic Church as well as the Old Catholic Church, Lutheran congregations of Evangelical Catholic churchmanship, Anglican congregations of Anglo-Catholic churchmanship, and Western Rite Orthodox communities. It is a prayer to the Triune God, which also includes invocations for the intercession of the Blessed Virgin Mary, the Angels and all the martyrs and saints upon whom Christianity was founded, and those recognised as saints through the subsequent history of the church. Following the invocation of the saints, the Litany concludes with a series of supplications to God to hear the prayers of the worshippers. It is most prominently sung during the Easter Vigil, All Saints' Day, and in the liturgy for conferring Holy Orders, the Consecration of a Virgin and reception of the perpetual vows of a religious or a diocesane hermit.