AND when he had said this, he breathed on them, and saith unto them, Receive ye the Holy Ghost.
BUT we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
2 Corinthians 3:18
[PAUL] says that Christ will not be formed in them save by partaking of the Holy Spirit, and living according to the law of the Gospel.
Therefore, as in the firstfruits of creation, which is made regenerate into incorruption and glory and into the Image of God, Christ establishes anew His own Spirit in His disciples.
For it was necessary that we should also perceive this truth, namely, that He brings down and grants the Spirit unto us.
St Cyril of Alexandria (+444), Commentary on St John’s Gospel Book XII (On John 20:22). Translation from CCEL.
CREATE in me a clean heart, O God; and renew a right spirit in my inward parts.
Cast me not away from thy presence; and remove not thy holy Spirit from me.
Restore to me the joy of thy salvation: establish me with thy directing Spirit.