"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. While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is My beloved Son, in whom I am well pleased; hear ye Him. And when the disciples heard it, they fell on their face, and were sore afraid. And Jesus came and touched them, and said, Arise, and be not afraid. And when they had lifted up their eyes, they saw no man, save Jesus only. And as they came down from the mountain, Jesus charged them, saying, Tell the vision to no man, until the Son of Man be risen again from the dead." Matthew 17:1-9

It is not the privilege of three - Peter, James and John
nor the presence of two - Moses and Elijah
but the pre-eminence of One - the Beloved Son
by the proclamation of God, the Father