John Chrysostom
See how Peter also defends himself on this occasion. As for what he answers after such an event, listen to the evangelist, who narrates thus: “Then Peter said, ‘Can anyone forbid water, that these should not be baptized, who have received the Holy Spirit just as we have?’” Do you see toward what he directed the matter, and how he desired to accomplish it? Thus he already had this in mind beforehand. “Water,” he says, “who can forbid?” He almost refutes those who opposed it and asserted that this should not be done. Everything has taken place, he says. The most necessary thing has been fulfilled, that is, the baptism with which we also were baptized. Therefore he prepares a speech about the Gentiles, in which he shows that they were no longer Gentiles once faith had appeared in them.
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Thus it is in no way astonishing that they received the Spirit before baptism. The same thing also happened with us. Here Peter shows that they were baptized not as the others were, but much better. Therefore the result was fully achieved: they could say nothing more, but had to acknowledge them, at least in this respect, as equal to themselves.