John Chrysostom
Catena Aurea · Lukasevangelium 24
Then opened he their understanding, that they might understand the Scriptures, And said unto them, Thus it is written, and thus it behoved Christ to suffer, and to rise from the dead the third day: And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem. And ye are witnesses of these things. 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.
(ut sup.) But why did not the Spirit come while Christ was present, or immediately on His departure? Because it was fitting that they should become desirous of grace, and then at length receive it. For we are then most awakened towards God, when difficulties press upon us. It was necessary in the mean time that our nature should appear in Heaven, and the covenants be completed, and that then the Spirit should come, and pure joys be experienced. Mark also what a necessity He imposed upon them of being at Jerusalem, in that He promised that the Spirit should there be given them. For lest they should again flee away after His resurrection, by this expectation, as it were a chain, He kept them all theretogether. But He says, until ye be endued from on high. He did not express the time when, in order that they may be constantly watchful. But why then marvel that He does not reveal to us our last day, when He would not even make known this day which was close at hand.