The Transfiguration of Jesus is an episode in the New Testament narrative in which Jesus is transfigured and becomes radiant upon a mountain. The Synoptic Gospels (Matthew 17:1–9, Mark 9:2-8, Luke 9:28–36) describe it, and 2 Peter 1:16–18 refers to it.

In these accounts, Jesus and three of his apostles go to a mountain (the Mount of Transfiguration). On the mountain, Jesus begins to shine with bright rays of light. Then the prophets Moses and Elijah appear next to him and he speaks with them. Jesus is then called "Son" by a voice in the sky, assumed to be God the Father, as in the Baptism of Jesus.

The Transfiguration is one of the miracles of Jesus in the Gospels. This miracle is unique among others that appear in the Canonical gospels, in that the miracle happens to Jesus himself. Thomas Aquinas considered the Transfiguration "the greatest miracle" in that it complemented baptism and showed the perfection of life in Heaven. The Transfiguration is one of the five major milestones in the gospel narrative of the life of Jesus, the others being Baptism, Crucifixion, Resurrection, and Ascension.

In Christian teachings, the Transfiguration is a pivotal moment, and the setting on the mountain is presented as the point where human nature meets God: the meeting place for the temporal and the eternal, with Jesus himself as the connecting point, acting as the bridge between heaven and earth.

Presence of prophets

The presence of the prophets next to Jesus and the perceptions of the disciples have been subject to theological debate. Origen was the first to comment that the presence of Moses and Elijah represented the "Law and the Prophets", effectively referring to the Torah or the Pentateuch. Martin Luther, continued to see them as the Law and the Prophets respectively, and their recognition of and conversation with Jesus as a symbol of how Jesus fulfils "the law and the prophets" (Matthew 5:17–19, see also Expounding of the Law).

The real presence of Moses and Elijah on the mount is rejected by those churches and individuals who believe in "soul sleep" (Christian mortalism) until resurrection. Several commentators have noted that Jesus describes the transfiguration using the Greek word orama (Matthew 17:9), according to Thayer more often used for a supernatural "vision" than for real physical events, and concluded that Moses and Elijah were not truly there.

Feast and commemorations

The Feast of the Transfiguration is celebrated by various Christian denominations. The origins of the feast are less than certain and may have derived from the dedication of three basilicas on Mount Tabor. The feast was present in various forms by the 9th century, and in the Western Church was made a universal feast on August 6 by Pope Callixtus III to commemorate the Siege of Belgrade (1456)

In the Syriac Orthodox, Indian Orthodox, Revised Julian Calendars within Eastern Orthodoxy, Roman Catholic, and Anglican churches, the Feast of the Transfiguration is observed on 6 August. In those Orthodox churches which continue to follow the Julian Calendar, August 6 falls on August 19 of the Gregorian Calendar. Transfiguration is considered a major feast, numbered among the twelve Great Feasts in Orthodoxy. In all these churches, if the feast falls on a Sunday, its liturgy is not combined with the Sunday liturgy, but completely replaces it.

In some liturgical calendars (e.g. the Lutheran and United Methodist) the last Sunday in the Epiphany season is also devoted to this event. In the Church of Sweden and the Church of Finland, however, the Feast is celebrated on the seventh Sunday after Trinity, the eighth Sunday after Pentecost.

In the Roman rite, the gospel periscope of the Transfiguration is read on the second Sunday of Lent, whose liturgy emphasizes the role the Transfiguration had in comforting the Twelve Apostles, giving them a powerful proof of his divinity, and a prelude to the glory of the Resurrection on Easter.