Small monastic communities formed as early as the third century around the Burning Bush. As Sinai priestmonk Father Justin says, the monks "were coming to the edge of the inhabitable world. It was such a harsh desert, people came here for the silence and because this had been the place sanctified by the revelations of God."

The Emperor Constantine ended the persecution of the Christians. Having seen the sign of the Cross in the heavens at the decisive moment when he was marching towards Rome, he desired to found a church at the place of the Crucifixion and Resurrection of Christ that would be the most splendid church in all the empire. He appointed his mother Helen as Augusta, and gave her unlimited access to the imperial treasury, requesting that the Church of the Holy Sepulchre be adorned with precious marbles, and its ceiling coffered and gilded. The Augusta Helen went to Jerusalem in the year AD 327, and the monks of Sinai appealed to her for the construction of a church at the site of the Burning Bush. This chapel is sometimes referred to as the Chapel of Saint Helen, and is dated to the year AD 330.

From the fourth century on, the area became a destination for pilgrims, as seen in the well-known travel account of the Spanish nun Egeria. However, there were also attacks by nomadic tribes, including the massacre of the Holy fathers slain at Mount Sinai and at Raitho, the closest port of entry by sea to the Sinai monastic enclaves. In the fifth century, the first local Church authority, the Bishopric of Pharan was established, and in the sixth, at the request of the monks, Byzantine Emperor Justinian built a magnificent basilica for the Sinai monks, dedicated to the Transfiguration of Christ, surrounded by granite walls strong enough to withstand nomadic raids.

“Like a vision of Heaven in the wilderness of Moses,” the basilica’s rare Transfiguration mosaic reflects the magnitude of the divine promise revealed to mankind on Sinai.

The revelation of the mystery begun in the Old Testament when Christ mystically appeared to Moses in the Burning Bush is completed in the New. This of course takes place at the Transfiguration, when the blinding Light of Christ’s divinity is suddenly revealed to His apostles Peter, James, and John. As Moses radiated with light after his experience on Sinai, the light of the Son of man is disclosed to all humanity whose nature He assumed – for “God became man that man might become god.” Thus it is through the Transfiguration, whose golden mosaic fills the main apse of Sinai’s sixth century basilica, that the meeting of Old and New Testaments takes place in the radiance of divine vision.

Having “died ten thousand times for God’s decrees” in surpassing their fears to serve the Lord, Moses and Prophet Elias, who stand on either side of Christ in the mosaic, had each encountered the Word of God on Sinai before He took on flesh. “For it is Christ who gave the Law … naturally invisible yet perceived in light,” wrote Saint Gregory of Sinai.  Therefore Moses exults with unspeakable joy, Gregory says, to see the glory of Christ revealed openly at His Transfiguration.

A chapel dedicated to the Holy Trinity marks the ground where Moses received the Ten Commandments on the summit of the Holy Mountain. At some distance below, another contains the cave where God revealed His presence to Elias in a gentle breeze. With renewed splendor in the basilica far below, the luminous prophets yet reflect the light of divine encounter, following a monumental restoration of the mosaic conducted between 2005 and 2010 in collaboration with the Monastery fathers by Rome’s Center for Archaeological Conservation. (For a video on the restoration, please see this link.)

During the sumptuous monastic services, as a Sinai monk Saint Gregory would have had ample opportunity to contemplate the plan of the celebrated mosaic, as reflected in his Discourse on the Transfiguration. Moses and Elias appear, one from the grave, the other as from heaven, he emphasizes, in order to clarify that Christ is not one of their number, as some had surmised. Instead He is the God of the Law and Prophets they symbolize, the source and fulfillment of every prophetic word. Therefore, their sudden appearance proves Christ to command the “power of both death and life,” for while Moses had undergone death, Elias was wondrously swept up as to heaven in a fiery chariot. Like Moses, Prophet Elias sought to see God on the heights of Sinai, and for pilgrims contemplating such longing during a morning’s attempt on the same craggy pinnacles, the connection is not lost: the one who strives mightily to see God will do so, in this life as well as the next.