ISB ~ Mark 9 v2

Peter … James … John:Three of Jesus’ closest companions. See note on 5:37.

• Anagogically(Rabanus Maurus, Comm. in Matt. 5, 17): Christ took three disciples up the mountain to signify that those who in this life believe in the Holy Trinity will in the next life behold the three Persons of the Godhead in heavenly glory.

high mountain:Traditionally identified with Mt. Tabor in lower Galilee. Theologically, this mountain is the New Covenant counterpart to Mt. Sinai, where Jesus manifests his divine splendor just as God revealed his glory to Moses (Ex 24:15-18) and Elijah (1 Kings 19:8-18) on Sinai (Horeb). See note on Mt 17:1-8.