The Passover affords a more than usually solemn day for baptism; when, withal, the Lord's passion, in which we are baptized, was completed. Nor will it be incongruous to interpret figuratively the fact that, when the Lord was about to celebrate the last Passover, He said to the disciples who were sent to make preparation, "You will meet a man bearing water." He points out the place for celebrating the Passover by the sign of water. After that, Pentecost is a most joyous space for conferring baptisms; wherein, too, the resurrection of the Lord was repeatedly proved among the disciples [Acts 1:3], and the hope of the advent of the Lord indirectly pointed to, in that, at that time, when He had been received back into the heavens [Acts 1:9], the angels told the apostles that "He would so come, as He had withal ascended into the heavens;" [Acts 1:11] at Pentecost, of course. But, moreover, when Jeremiah says, "And I will gather them together from the extremities of the land in the feast-day," he signifies the day of the Passover and of Pentecost, which is properly a "feast-day." However, every day is the Lord's; every hour, every time, is apt for baptism: if there is a difference in the solemnity, distinction there is none in the grace.
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 Spirit. The water, however, flows round the outside only, but the Spirit baptizes also the soul within, and that completely. And why do you wonder at this? Take an example from matter, a simple and common example, but one that helps the ordinary person. If 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 Spirit enters into the very inmost recesses of the soul?
Consider also how necessary He made it for them to abide in Jerusalem, by promising that the Spirit should be granted them. For lest they should again flee away after His Ascension, by this expectation, as by a bond, He keeps them to that spot. But having said, "Wait for the promise of the Father, which ye have heard of Me," He then adds, "For John truly baptized with water, but ye shall be baptized with the Holy Ghost not many days hence." For now indeed He gives them to see the difference there was betwixt Him and John, plainly, and not as heretofore in obscure hints; for in fact He had spoken very obscurely, when He said, "Notwithstanding, he that is least in the kingdom of heaven is greater than he:" but now He says plainly, "John baptized with water, but ye shall be baptized with the Holy Ghost." And he no longer uses the testimony, but merely adverts to the person of John, reminding the disciples of what he had said, and shows them that they are now become greater than John; seeing they too are to baptize with the Spirit. Again, He did not say, I baptize you with the Holy Ghost, but, "Ye shall be baptized:" teaching us humility. For this was plain enough from the testimony of John, that it was Christ Himself Who should baptize: "He it is that shall baptize you with the Holy Ghost and with fire;" wherefore also He made mention of John.
The Gospels, then, are a history of what Christ did and said; but the Acts, of what that "other Comforter" said and did. Not but that the Spirit did many things in the Gospels also; even as Christ here in the Acts still works in men as He did in the Gospels; only then the Spirit wrought through the Temple, now through the Apostles: then, He came into the Virgin's womb, and fashioned the Temple; now, into Apostolic souls: then in the likeness of a dove; now, in the likeness of fire. And wherefore? Showing there the gentleness of the Lord, but here His taking vengeance also, He now puts them in mind of the judgment likewise. For, when need was to forgive, need was there of much gentleness; but now we have obtained the gift, it is henceforth a time for judgment and examination.
But why does Christ say, "Ye shall be baptized," when in fact there was no water in the upper room? Because the more essential part of Baptism is the Spirit, through Whom indeed the water has its operation; in the same manner our Lord also is said to be anointed, not that He had ever been anointed with oil, but because He had received the Spirit. Besides, we do in fact find them receiving a baptism with water and a baptism with the Spirit, and these at different moments. In our case both take place under one act, but then they were divided. For in the beginning they were baptized by John; since, if harlots and publicans went to that baptism, much rather would they who thereafter were to be baptized by the Holy Ghost.
Then, that the Apostles might not say, that they were always having it held out to them in promises (for indeed Christ had already discoursed much to them concerning the Spirit, that they should not imagine It to be an impersonal Energy or Operation), that they might not say this, then, He adds, "not many days hence." And He did not explain when, that they might always watch: but, that it would soon take place, He told them, that they might not faint; yet the exact time He refrained from adding, that they might always be vigilant. Nor does He assure them by this alone; I mean, by the shortness of the time, but withal by saying, "The promise which ye have heard of Me." For this is not, saith He, the only time I have told you, but already I have promised what I shall certainly perform. What wonder then that He does not signify the day of the final consummation, when this day which was so near He did not choose to reveal? And with good reason; to the end they may be ever wakeful, and in a state of expectation and earnest heed.
But you shall be baptized with the Holy Spirit not many days from now. The apostles had not yet been baptized, not with water, but with the Holy Spirit, whom we understand they had already been baptized, either with John's baptism (as some suppose), or (what is more credible) with Christ's baptism. For the ministry of baptizing had not been such that it had baptized servants through whom others would be baptized, for the ministry of that memorable humility was not lacking, when He washed their feet. Therefore, when the Lord said: For John indeed baptized with water, He did not add: But you shall baptize, but: But you shall be baptized with the Holy Spirit. For neither the apostles nor their followers, who baptize even to this day in the Church, can baptize otherwise than John, that is, with water, but only by invoking the name of Christ, the interior power of the Holy Spirit is present, which, with a man providing the water, purifies both the souls and bodies of the baptized, which was not done in John's baptism. For the Spirit had not yet been given, because Jesus had not yet been glorified (John VII).
For John indeed baptized with water, but you will be baptized with the Holy Spirit. Baptisma in Greek is called tinctio in Latin. Wherefore, in some manuscripts we find it interpreted thus: For John indeed dipped with water, but you will be dipped in the Holy Spirit. Here the marvelous harmony of the words of the Lord and his precursor is evident. For he said to those whom he baptized, about the Lord: I baptized you with water, but he will baptize you with the Holy Spirit (Mark 1:8). And the Lord himself: John indeed baptized with water, but you will be baptized with the Holy Spirit. It should be noted as well that the baptism of the Lord in the Holy Spirit, which John had foretold, does not refer only to that time when the Apostles and other faithful of that time were baptized with water for the remission of sins, through the grace of the Holy Spirit given to them by the Lord; but also to this, when, with the Lord sending them, they received more fully the gifts of the same Spirit from heaven. But also now, whoever receives baptism for the remission of sins, is certainly baptized in the Holy Spirit, through whose gift they are both cleansed from all sins, and are aided so that they can progress in good deeds.
[AD 220] Tertullian on Acts 1:3-11