For they heard them. He expresseth what gifts of the Spirit were poured out upon them, and therewithal he noteth the use; to wit, that they had variety of tongues given them, so that they did glorify God with many tongues. Also, it may be gathered out of this place, that the tongues were given them not only for necessity, seeing the gospel was to be preached to strangers and to men of another language, but also to be an ornament and worship to the gospel. But ambition did afterward corrupt this second use, forasmuch as many did translate that unto pomp and vain glory which they had received to set forth the dignity of the heavenly wisdom, as Paul doth sharply reprove this fault in the Corinthians. Therefore, no marvel if God took away that shortly after which he had given, and did not suffer the same to be corrupted with longer abuse.

Speak with tongues - In other languages than their own native tongue, Acts 2:4.
And magnify God - And praise God.

And magnify God - They had got new hearts as well as new tongues; and, having believed with the heart unto righteousness, their tongues made confession unto salvation; and God was magnified for the mercy which he had imparted.

For they heard them speak with tongues,.... With divers tongues, which they had never learned, and before did not understand: and magnify God; they spoke of the wonderful works of God in these languages, as the apostles did at Pentecost, Acts 2:11 they spoke greatly in the praise of God, and gave thanks for his rich grace and mercy bestowed on them:
then answered Peter; as follows.

heard them speak with tongues and magnify God--As on the day of Pentecost it was no empty miracle, no mere speaking of foreign languages, but utterance of "the wonderful works of God" in tongues to them unknown (Acts 2:11), so here; but more remarkable in this case, as the speakers were perhaps less familiar with the Old Testament songs of praise.
Then answered Peter, Can any man forbid water . . . which have received the Holy Ghost, &c.--Mark, he does not say, They have received the Spirit, what need have they for water? but, Having the living discipleship imparted to them and visibly stamped upon them, what objection can there be to admitting them, by the seal of baptism, into the full fellowship of the Church?