And, behold, I send the promise of my Father upon you: but tarry ye in the city of Jerusalem, until ye be endued with power from on high. The promise of my Father - That is, the Holy Ghost, promised, John 15:26. See Acts 1:4; Acts 2:33.
Until ye be endued with power - The energy of the Holy Ghost was to be communicated to them for three particular purposes.
1. That he might be in them, a sanctifying comforter, fortifying their souls and bringing to their remembrance whatever Jesus had before spoken to them.
2. That their preaching might be accompanied by his demonstration and power to the hearts of their hearers, so that they might believe and be saved.
3. That they might be able to work miracles to confirm their pretensions to a Divine mission, and to establish the truth of the doctrines they preached.