The Feast of the Transfiguration is a very important feast for monks. According to the Gospels (Mt 17: 1-8; Mark 9: 2-8; Luke 9: 28-36), Jesus takes with him his closest disciples, Peter, James and John, and leads them to an isolated mountain top, and there he was transfigured before them. His divinity is manifested through a dazzling light. Moses and Elijah also appear and they speak to Jesus. Peter then exclaims, "Lord, it is good that we are here." A voice from heaven declares: "This is my beloved Son, listen to him." After coming back down the mountain with his disciples, Jesus announces for the second time his approaching Passion.
The event of the Transfiguration has always been understood by monks as a symbol of their vocation. Like Peter, James and John, they are invited by Jesus to leave the everyday world to follow him into the desert and behold his glory. The presence of Elijah and Moses, and the voice from heaven calling to listen to Jesus, evoke lectio divina, patient and loving study of the Word of God. The exclamation of Peter expresses with simplicity the happiness one feels living with and for Jesus. Monastic life is a foretaste of the joy of heaven. At the same time, the close link of the Transfiguration and the Passion of Jesus reminds monks that their lives in this world entail penance, knowing that joy will be complete only beyond death.
This is why the feast of the Transfiguration was propagated in the West by monks, especially by Peter the Venerable, Abbot of Cluny in the twelfth century. Originating centuries ago in the East, the date of August 6 was eventually settled upon, 40 days before the feast of the Triumph of the Cross (14 September) to highlight the link between the Transfiguration of Christ and his Passion. It was included in the Roman Calendar in 1457 in thanksgiving for the victory over the Turks at Belgrade, August 6, 1456.
The 4th antiphon of Lauds of the apostles of office draws a parallel between the privilege granted to Peter, James and John at the Transfiguration and the Beatitudes proclaimed in the Sermon on the mount.
Beati pacifici, beati mundo corde, quoniam ipsi Deum videbunt
Blessed are the peacemakers, blessed are the pure of heart, for they shall see God