What does Acts 1:12 mean?

Jesus took the disciples "as far as Bethany" (Luke 24:50), told them to expect the Holy Spirit (Acts 1:5), and rose into the clouds (Acts 1:9). While the disciples stood stunned at the sudden departure of their teacher and friend, two men, presumably angels, broke their reverie, telling them Jesus would return in the same way (Acts 1:10–11).

The Mount of Olives is actually a ridge with three summits, stretching two miles north to south, east of Jerusalem. Bethany is on the far, east side, about a mile and a half from Jerusalem. A Sabbath day's journey is less than a mile, so the exact travel of the disciples is unclear.

The Mount of Olives holds a significant place in the life of Jesus. It is where He started His ride in the triumphal entry (Matthew 21:1) and where He and the disciples slept from that day until the crucifixion (Luke 21:37). After the Last Supper, Jesus took the disciples to the garden of Gethsemane on the Mount of Olives where He was betrayed by Judas, abandoned by His friends, and arrested (Matthew 26:36, 47–56). And when Jesus returns, "his feet shall stand on the Mount of Olives that lies before Jerusalem on the east, and the Mount of Olives shall be split in two from east to west by a very wide valley" (Zechariah 14:4), inaugurating Jesus' destruction of the Antichrist and His reign in the millennial kingdom.

The disciples no longer have the immediate presence of Jesus, but they have each other. They will join in an upper room and pray, about 120 people total (Acts 1:13–15). Before they even receive the Holy Spirit, the first task of the incipient church is to seek God's guidance.