The event on the Mt. of Transfiguration is understood more fully when we consider Moses’ encounter with God on Mt. Sinai. With the glory of God upon him, Moses reminds the people that they saw His mighty works of deliverance in Egypt, are in covenant/reciprocal agreement with Him, and now must listen to Him. When the disciples go up the mountain with Jesus and they see Him glorified, they also are commanded to listen to Him.
It when we behold God’s glory and obey Him that we too can be transformed (from glory to glory) into the people that He wants us to be.