“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 17:9 — Greek Interlinear
Church Fathers on Matthew 17:9
While they thought only of an earthly tabernacle of boughs or tents, they are overshadowed by the covering of a bright cloud; 'While he yet spake there came a bright cloud and overshadowed them.
When the Lord threatens, He shews a dark cloud, as on Sinai [margin note: Ex 19:9,16]; but here where He sought not to terrify but to teach, there appeared a bright cloud.
The bright cloud overshadowing the Saints is the Power of the Father, or perhaps the Holy Spirit; or I may also venture to call the Saviour that bright cloud which overshadows the Gospel, the Law, and the Prophets, as they understand who can behold His light in all these three.