The Feast of the Transfiguration of Jesus is celebrated by the most Christian denominations on August 06, 2017. 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.
The Transfiguration is the second of the "Three Feasts of the Saviour in August", the other two being the Procession of the Cross on August 1 and the Icon of Christ Not Made by Hand on August 16. The Transfiguration is preceded by a one-day Forefeast and is followed by an Afterfeast of eight days, ending the day before the Forefeast of the Dormition.
The Transfiguration of Jesus is an event reported in the New Testament in which Jesus is transfigured and becomes radiant upon a mountain. 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, 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.
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. (With material from: Wikipedia)