Hilary of Poitiers
Catena Aurea · Matthäusevangelium 17
And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart, And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light. And, behold, there appeared unto them Moses and Elias talking with him. Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias.
Also that Moses and Elias only out of the whole number of the saints stood with Christ, means, that Christ, in His kingdom, is between the Law and the Prophets; for He shall judge Israel in the presence of the same by whom He was preached to them.