Cyril of Jerusalem:
He came down to clothe the Apostles with power, and to baptize them.
For the Lord says, ye shall be baptized with the Holy Ghost not many days hence (Acts 1:5).
This grace was not in part, but His power was in full perfection.
For as he who plunges into the waters and is baptized is encompassed on all sides by the waters, so were they also baptized completely by the Holy Ghost.
The water however flows round the outside only, but the Spirit baptizes also the soul within, and that completely.
And wherefore wonderest thou? Take an example from matter; poor indeed and common, yet useful for the simpler sort.
The fire passing in through the mass of the iron makes the whole of it fire, so that what was cold becomes burning and what was black is made bright.
If fire which is a body thus penetrates and works without hindrance in iron which is also a body, why wonder that the Holy Ghost enters into the very inmost recesses of the soul?
And lest men should be ignorant of the greatness of the mighty gift coming down to them, there sounded as it were a heavenly trumpet.
For suddenly there came from heaven a sound as of the rushing of a mighty wind (Acts 2:2), signifying the presence of Him who was to grant power unto men to seize with violence the kingdom of God; that both their eyes might see the fiery tongues, and their ears hear the sound.
And it filled all the house where they were sitting; for the house became the vessel of the spiritual water; as the disciples sat within, the whole house was filled.
Thus they were entirely baptized according to the promise, and invested soul and body with a divine garment of salvation.
And there appeared unto them cloven tongues like as of fire, and it sat upon each of them; and they were all filled with the Holy Ghost.
They partook of fire, not of burning but of saving fire; of fire which consumes the thorns of sins, but gives lustre to the soul.
This is now coming upon you also, and that to strip away and consume your sins which are like thorns, and to brighten yet more that precious possession of your souls, and to give you grace; for He gave it then to the Apostles.
And He sat upon them in the form of fiery tongues, that they might crown themselves with new and spiritual diadems by fiery tongues upon their heads. A fiery sword barred of old the gates of Paradise; a fiery tongue which brought salvation restored the gift.
Cyril of Jerusalem (c. 313-386): Catechetical Lectures 17, 14-15.
