(Verse 12) - Then returned they unto Jerusalem - In Luke 24:52, we are told that they worshipped Jesus before they returned, and it is probable that the act of worship to which he refers was what is mentioned in this chapter their gazing intently on their departing Lord.

From the mount called Olivet - From the Mount of Olives. (See Matt. 21:1). The part of the mountain from which he ascended was the eastern declivity, where stood the little village of Bethany, (Luke 24:50).

A Sabbath-day’s journey - As far as might be lawfully traveled by a Jew on the Sabbath. This was 2,000 paces or cubits, or seven furlongs and a half - not quite one mile. (See Matt. 24:20). The distance of a lawful journey on the Sabbath was not fixed by the laws of Moses, but the Jewish teachers had fixed it at 2,000 paces. This measure was determined on because it was a tradition that in the camp of the Israelites, when coming from Egypt, no part of the camp was more than 2000 paces from the tabernacle, and over this space, therefore, they were permitted to travel for worship. Perhaps, also, some countenance was given to this from the fact that this was the extent of the suburbs of the Levitical cities, (Num. 35:5). Mount Olivet was only 5 furlongs from Jerusalem, and Bethany was 15 furlongs. But on the eastern declivity of the mountain the tract of country was called, for a considerable space, the region of Bethany; and it was from this place that the Lord Jesus ascended.

(Verse 13) - Were come in - To Jerusalem.

They went up into an upper room - The word   , here translated “upper room,” occurs only four times in the New Testament: (Acts 9:37, “She (Dorcas) was sick and died; whom when they had washed, they laid her in an upper chamber” (see also Acts 9:39); 20:8, “And there were many lights in the upper chamber where they were gathered together.”) The room so designated was an upper chamber used for devotion, or as a place where to lay the dead before burial, or occasionally for conversation, etc. Here it evidently means the place where they were assembled for devotion. Luke 24:53 says they were continually “in the temple” praising and blessing God; and some have supposed that the upper room here designated was one of the rooms in the temple. But there is no evidence of that, and it is not very probable. Such a room as that here referred to was a part of every house, especially in Jerusalem; and the disciples probably selected one where they might be together, and yet so retired that they might be safe from the Jews.

The expression used in Luke 24:53, “They were continually in the temple,” signifies no more than that this was a frequent or customary resort; they were always in the temple at the usual seasons of devotion, or they were in the constant habit of resorting thither.

Where abode - Where were remaining. This does not mean that this was their permanent habitation; but they remained there waiting for the descent of the Holy Spirit.

Peter  - All the apostles were there which Jesus had at first chosen except Judas, Luke 6:13-16.