Luke 24:49

And behold, I send the promise of my Father upon you
By which is meant the promise of the Spirit, called the promise of the Father, because he was promised by the Father to be sent, and poured on the saints in the times of the Messiah, ( Isaiah 44:3 ) ( Joel 2:28 ) and because Christ promised to pray the Father for him, and to send him from him; and that the Father should send him in his name, who would fit and qualify them for, and assist them in bearing a testimony for him; since he would teach them all things, lead them into all truth, take of the things of Christ, and show them to them, and bring to their remembrance all things they had seen and heard: and this promise of the Father was to be sent in a very short time, in ten days time, as accordingly it was; and might be very properly said to be sent "upon" them, since, when he was sent down, he sat upon them in the appearance of fire; and this being a marvellous thing, as well as of great moment and importance, it is introduced with a "behold", as a note both of admiration and attention.

But tarry ye in the city of Jerusalem;
for the space of ten days; here they were to continue during that time, and not depart thence; yea, they were to sit there, as the word used signifies: they were to sit still, and be silent; they were not to begin to preach; they were only to attend to prayer and Christian conversation, and to wait for the Spirit, the promise of the Father; and who also is designed in the following clause:

until ye be endued with power from on high;
the Spirit of God is a spirit of might, and of power, as well as of knowledge, of understanding, of counsel, of love, and of a sound mind; whereby they were to be fortified, and inspired with courage and greatness of soul, so as to look their greatest adversaries in the face with boldness and intrepidity, and freely, and without fear, speak unto them; and whereby their ministrations would be succeeded to the conversion of many souls; and accordingly so it was: for after the Spirit was poured out upon them, they who before were timorous and fearful, came forth publicly, with undaunted courage, and resolution, and boldness, to the amazement of their adversaries; and their preaching was with the demonstration of the Spirit, and of power; who may be said to be "from on high", since he descended from heaven upon them; and they may be said to be "endued", or "clothed" with him, since there was such an extra ordinary and plentiful effusion of his gifts and graces on them: and now they were to wait in Jerusalem for this, that in the place where the Spirit had been dishonoured and blasphemed, and the unpardonable sin against him had been committed by the Scribes and Pharisees, the might be in a most visible and signal manner honoured; and also, because the doctrine of the Lord was to go out of Zion, and the word of the Lord out of Jerusalem. The Vulgate Latin version leaves out the word "Jerusalem", and reads only, "sit ye in the city until" but then no other city can be designed.