By Fr Robert Barron (wordonfire.org)
The Transfiguration takes place on a mountain, and this right away places it in relation to the Old Testament. Abraham is willing to sacrifice his son on a mountain; Noah’s ark comes to rest on Mt. Ararat; the law is given to Moses on Mt. Sinai; Elijah challenges the priests of Baal on Mt. Carmel; Jerusalem is built on the top of Mt. Zion. Mountains are places of encounter with God.
In the New Testament, Jesus gives the law on a mountain, the Sermon on the Mount; he dies on Mt. Calvary; and, in a climactic moment in his public life, he brings three of his disciples to the top of a mountain – and there he is transfigured before them.
What is especially stressed here is the manner in which Jesus represents the fulfillment of the Old Testament revelation, economically symbolized by the two figures with whom he converses: Moses, representing the law, and Elijah, representing the prophets. When a Jew of Jesus’ time would speak of the Scriptures, he would use a shorthand: the Law and the Prophets.
In speaking to Moses and Elijah, in the glory of the Transfiguration, Jesus signals that he brings the law and the prophets to their proper fulfillment. N.T. Wright, the great contemporary Biblical scholar, says that the Old Testament remained, fundamentally, a story without an ending, a promise without fulfillment…that is, until Jesus came into history.