Acts 2:41 - Joseph Benson’s Commentary on the Old and New Testaments

Then they that gladly received his word, &c. The apostle's exhortation was not given in vain; many were awakened and savingly brought to God by it; for the influence of the Holy Spirit accompanied it, and wrought wonders thereby. Many of the same persons that had been eye-witnesses of the death of Christ, and of the prodigies that had attended it, and were not at all influenced by them, were now effectually wrought upon by the preaching of the word, and found it the power of God to their salvation. Such were baptized Gladly receiving the word, believing with the heart, they made confession with the mouth, and enrolled themselves among the disciples of Christ, by that sacred rite and ceremony which he had instituted. Hereby there were added to the hundred and twenty disciples of Christ about three thousand souls that same day; the conversion of whom, by the word now spoken, was a greater work than the feeding of four or five thousand with a few loaves and fishes. Let it be observed here, they who are joined to Christ, ought to join themselves to the disciples of Christ, and be united with them: when we take God for our God, we must take his people for our people. It is commonly said, that all these were converted by one sermon, but, as has been intimated on Acts 2:14, it is probable, that while Peter was preaching in the Chaldaio-Syriac language, the other apostles were preaching at some small distance, much to the same purpose, in other languages; and it is not surely to be imagined, that none of them but Peter should be blessed as the means of converting any souls; not to insist upon it that he himself might deliver several discourses that day (and it was τη ημερα εκεινη, in that day, that the number here spoken of was added) to different auditories, when the concourse of people was so great, and their languages so various.