John Calvin Commentary Acts 2:47

"praising God, and having favor with all the people. And the Lord added to them day by day those that were saved." — Acts 2:47 (ASV)

Having favor. This is the fruit of an innocent life: to find favor even among strangers. Yet we need not doubt that they were also hated by many. But although he speaks generally of the people, he means only that part which was sound and not yet infected with any poison of hatred; he signifies briefly that the faithful conducted themselves so that the people regarded them very favorably for their innocence of life.

The Lord added daily. He shows in these words that their diligence was not without profit; they made every effort, as much as was in them, to gather into the Lord’s sheepfold those who wandered and went astray. He says that their labor in this was not in vain, because the Lord increased His Church daily.

And surely, when the Church is diminished rather than increased, that is to be attributed to our sloth, or rather, our presumption. And although all of them labored resolutely to expand the kingdom of Christ, yet Luke ascribes this honor to God alone: that He brought strangers into the Church.

And surely, this is His own particular work. For ministers accomplish nothing by planting or watering unless He makes their labor effective by the power of His Spirit (1 Corinthians 3). Furthermore, we must note that he says that those were gathered into the Church who were to be saved.

For he teaches that this is the means to attain salvation, if we are incorporated into the Church. For just as there is no remission of sins, so also there is no hope of salvation.

Furthermore, this is an excellent comfort for all the godly: that they were received into the Church so that they might be saved, just as the Gospel is called the power of God unto salvation to all that believe (Romans 1:16).

Now, since God gathers only a part, or a certain number, this grace is restricted to election, so that it is the first cause of our salvation.