Theophylact of Ohrid
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.
Afterwards, lest they should be troubled at the thought, How shall we private individuals give our testimony to the Jews and Gentiles who have killed Thee? He subjoins, And, behold, I send the promise of my Father upon you, &c. which indeed He had promised by the mouth of the prophet Joel, I will pour my Spirit upon all flesh. (Joel 2:18.)