What does Mark 9:2 mean?

Jesus and the disciples had gone from the east side of the Sea of Galilee, back to Galilee on the west side, then up to the top of the Sea to Bethsaida (Mark 8:22). From Bethsaida, they traveled north to Caesarea Philippi where Peter affirmed Jesus is the Messiah (Mark 8:27–30) and Jesus warned them of His coming death and resurrection (Mark 8:31–38). It is now six days later.

Scholars suggest that the "high mountain" could be Mt. Hermon, northeast of Caesarea Philippi. Mt. Hermon is first mentioned in Deuteronomy 3:8. It served as the northwestern boundary of the territory the Israelites conquered on the east side of the Jordan. Others suggest they are on Mt. Meron, northwest of the Sea of Galilee. Mt. Meron is a seven-hour hike to Capernaum, which better fits the account that they are one day away (Luke 9:37) from the Jewish scribes who are arguing with the remaining disciples (Mark 9:14).

In most Bibles, in Matthew and Luke's accounts, the text in Mark 9:1 is grouped with the previous section, but it is directly related to the transfiguration. While Jesus' words in Mark 9:1 seem to refer to the deliverance of Israel and the earthly reign of the Messiah, Peter, James, and John learn otherwise. "Transfigured" comes from the Greek root word metamorphoo. It means to change forms. In this case, while Jesus prays (Luke 9:29), His body changes from a purely human form to one that more accurately displays His deity and glory.

Matthew 17:1 says six days; Luke 9:28 says "about eight days." It could be that Greeks counted portions of days differently. Mark's specific "after six days" is unique in his Gospel; ordinarily, he uses the term "immediately." His precision gives evidence to the belief that the transfiguration is directly related to Jesus' promise in Mark 9:1.

If the twelve disciples are the inner core of Jesus' followers, Peter, James, and John are the center of that core. Only they saw Jesus raise Jairus' daughter (Mark 5:37), and Jesus asked only them to draw near to Him in the Garden of Gethsemane before He was betrayed (Mark 14:33). They also represent the extremes of the Twelve: James was the first to be martyred (Acts 12:2), John lived the longest, and Peter was arguably forgiven the most (Luke 7:41–50) and had the greatest leadership role in the early church.