“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 Elijah 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 Elijah. 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, KJV)
According to the scripture Matthew 17:1-19 it was clearly stated that Matthew was not on the mountain of transfiguration even if he had the account of what happened on the mountain which I feel was Divine revelation from the most high God.
From the last verse above we could see were Jesus was charging the disciple's to tell no man untill he has reason it was actually a confidential information which Jesus felt it was not for the consumption of all the disciple's , their is this saying that many are called but few are choose so Jesus decided to choose the few disciples which he felt was relevant for that accounts.
Thanks