The account of the supernatural transformation of Christ is recorded in the synoptic gospels (Mark 9:2-8; Matt. 17:1-8; Luke 9:28-36). There is no mention of the event in the gospel of John, but there is a reference at 2 Pet. 1:18.
In the context of the the Bible, the mention of Moses (the Law) and Elijah (the Prophets) standing with Jesus at his transfiguration and the cloud visible to the disciples as a symbol for the divine presence (Exod. 33:7-11) signify the relationship of this New Testament account to the ancient Jewish Old Testament account as told in Exodus 24:16.
To strengthen the connection of this New Testament event with the Old Testament, the three dwellings (or tents, booths) proposed by Peter to shade Jesus, Moses, and Elijah reference the Feast of Tabernacles, celebrated annually by the Jews. During this week-long event, in order to remember the wilderness experience of their ancestors, the Jews lived in booths or tents like their ancestors were believed to have done in the wilderness (Lev. 23:42) and would do so again in the Messianic age.
Moses’s face once shone with the reflected glory of God (Exod. 34:29); on the mount, Jesus’s figure shone with its own glory, and his clothes were ‘dazzling white’. The human life of Jesus was not merely a revelation to the disciples but also a promise of what all believers are destined to enjoy–the ultimate religious union of the human person with God, meaning not that a human being might become a god, or part of a god, but that the divine image might be finally and fully manifested in a created being whose life had been redeemed with the righteousness of Christ.¹
And all of us, with unveiled faces, seeing the glory of the Lord as though reflected in a mirror, are being transformed into the same image from one degree of glory to another; for this comes from the Lord, the Spirit. II Corinthians 3:18
¹”transfiguration.” In A Dictionary of the Bible. Ed. W. R. F. Browning. Oxford Biblical Studies Online. 02Mar2019<http://www.oxfordbiblicalstudies.com/article/opr/t94/e1945>.