19 But Peter who had the Holy Ghost, and who knew what he possessed, says, Men of Israel, you who preach Joel, but know not the things which are written, these men are not drunken as you suppose. Drunken they are, not however as you suppose, but according to that which is written, They shall be drunken with the fatness of your house; and you shall make them drink of the torrents of your pleasure. They are drunken, with a sober drunkenness, deadly to sin and life-giving to the heart, a drunkenness contrary to that of the body; for this last causes forgetfulness even of what was known, but that bestows the knowledge even of what was not known.
They are drunken, for they have drunk the wine of the spiritual vine, which says, I am the vine and you are the branches. But if you are not persuaded by me, understand what I tell you from the very time of the day; for it is the third hour of the day. For He who, as Mark relates, was crucified at the third hour, now at the third hour sent down His grace. For His grace is not other than the Spirit's grace, but He who was then crucified, who also gave the promise, made good that which He promised.
And if you would receive a testimony also, Listen, he says: “But this is that which was spoken by the prophet Joel; And it shall come to pass after this, says God, I will pour forth of My Spirit — (and this word, I will pour forth, implied a rich gift; for God gives not the Spirit by measure, for the Father loves the Son, and has given all things into His hand; and He has given Him the power also of bestowing the grace of the All-holy Spirit on whomsoever He will)— I will pour forth of My Spirit unto all flesh, and your sons and your daughters shall prophesy; and afterwards, Yea, and on My servants and on My handmaidens I will pour out in those days of My Spirit, and they shall prophesy.”
The Holy Ghost is no respecter of persons; for He seeks not dignities, but piety of soul. Let neither the rich be puffed up, nor the poor dejected, but only let each prepare himself for reception of the Heavenly gift.
Source: Catechetical Lectures (New Advent)