6 But what is meant by this which he says, “For the Spirit was not yet given, because Jesus was not yet glorified?” He is understood to say this in a sense that is evident. For the meaning is not that the Spirit of God, which was with God, was not in being; but was not yet in them who had believed on Jesus. For thus the Lord Jesus disposed not to give them the Spirit of which we speak, until after His resurrection; and this not without a cause. And perhaps if we inquire, He will favor us to find; and if we knock, He will open for us to enter.
Piety knocks, not the hand, though the hand also knocks, if it cease not from works of mercy. What then is the cause why the Lord Jesus Christ determined not to give the Holy Spirit until He should be glorified? Which thing before we speak of as we may be able, we must first inquire, lest that should trouble any one, in what manner the Spirit was not yet in holy men, while we read in the Gospel concerning the Lord Himself newly born, that Simeon by the Holy Spirit recognized Him; that Anna the widow, a prophetess, also recognized Him; that John, who baptized Him, recognized Him; that Zacharias, being filled with the Holy Ghost, said many things; that Mary herself received the Holy Ghost to conceive the Lord. We have therefore many preceding evidences of the Holy Spirit before the Lord was glorified by the resurrection of His flesh.
Nor was it another spirit that the prophets also had, who proclaimed beforehand the coming of Christ. But still, there was to be a certain manner of this giving, which had not at all appeared before. For nowhere do we read before this, that men being gathered together had, by receiving the Holy Ghost, spoken in the tongues of all nations. But after His resurrection, when He first appeared to His disciples, He said to them: “Receive the Holy Ghost.” Of this giving then it is said, “The Spirit was not given, because Jesus was not yet glorified.
And He breathed upon their faces,” He who with His breath enlivened the first man, and raised him up from the clay, by which breath He gave a soul to the limbs; signifying that He was the same who breathed upon their faces, that they might rise out of the mire and renounce their miry works. Then, after His resurrection, which the evangelist calls His glorifying, did the Lord first give the Holy Ghost to His disciples. Then having tarried with them forty days, as the book of the Acts of the Apostles shows, while they were seeing Him and companying with Him, He ascended into heaven in their sight.
There at the end of ten days, on the day of Pentecost, He sent the Holy Ghost from above. Which having received, they, who had been gathered together in one place, as I have said, being filled withal, spoke in the tongues of all nations.
Source: Tractates on the Gospel of John (New Advent)