What does Mark 9:1 mean?Verse and chapter divisions were not part of the original manuscripts of the Bible. This verse is more accurately considered part of the preceding section, also described in Matthew 16:24–28 and Luke 9:23–27.
"And he said to them" likely means the entire section is a summary of a longer conversation. "Truly, I say to you…" may mean that Jesus is giving an oath.
Unlike Mark 8:38, which refers to a time when Jesus will come "in the glory of his Father with the holy angels," the event referred to here is just a glimpse of the kingdom of God. Scholars have had many discussions and debates as to what this event is. Possibilities include the transfiguration (which immediately follows), the resurrection, the ascension (Acts 1:6–11), Pentecost (Acts 2:1–13), or just the growing mustard seed of the expanding church (Mark 4:30–32).
The most likely answer is that Jesus means the transfiguration. Although the wording sounds awkward if it refers to an event that will happen within a week, the facts are that Peter, James, and John see the glorified Christ before they die. The other disciples will Jesus in His glorified, resurrected body, but they do not see Him transfigured and affirmed by God (Mark 9:2–7).
This supports the idea that the kingdom of God means more than heaven. The kingdom of God is any situation where God's sovereignty, authority, power, and glory are manifest. Peter, James, and John experience this as they watch the transfigured Jesus speaking to Elijah and Moses and hear God say, "This is my beloved Son; listen to him" (Mark 9:7).