Luke 24:49

But let us consider how according to John they received the Holy Spirit, while here they are ordered to stay in the city until they should be endued with power from on high. Either He breathed the Holy Spirit into the eleven, as being more perfect, and promised to give it to the rest afterwards; or to the same persons He breathed in the one place, He promised in the other. Nor does there seem to be any contradiction, since there are diversities of graces. Therefore one operation He breathed into them there, another He promised here. For there the grace of remitting sins was given, which seems to be more confined, and therefore is breathed into them by Christ, that you may believe the Holy Spirit to be of Christ, to be from God. For God alone forgiveth sins. But Luke describes the pouring forth of the grace of speaking with tongues.

(Hom. i. in Act.) But as a general does not permit his soldiers who are about to meet a large number, to go out until they are armed, so also the Lord does not permit His disciples to go forth to the conflict before the descent of the Spirit. And hence He adds, 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 there together. 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. Or He said, Receive ye the Holy Spirit, that He might make them fit to receive it, or indicated as present that which was to come.

(de Trin. 15. c. 26.) Or the Lord after His resurrection gave the Holy Spirit twice, once on earth, because of the love of our neighbour, and again from heaven, because of the love of God.

(de Past. 3. c. 25.) They then are to be warned, whom age or imperfection hinders from the office of preaching, and yet rashness impels, lest while they hastily arrogate to themselves so responsible an office, they should cut themselves off from the way of future amendment. For the Truth Itself which could suddenly strengthen those whom it wished, in order to give an example to those that follow, that imperfect men should not presume to preach, after having fully instructed the disciples concerning the virtue of preaching, commanded them to abide in the city, until they were endued with power from on high. For we abide in a city, when we keep ourselves close within the gates of our minds, lest by speaking we wander beyond them; that when we are perfectly endued with divine power, we may then as it were go out beyond ourselves to instruct others.

But concerning the power, that is, the Holy Spirit, the Angel also says to Mary, And the power of the Highest shall overshadow thee. (Luke 1:35.) And the Lord Himself says elsewhere, For I know that virtue is gone out of me. (Luke 8:45.)