John Calvin Commentary Acts 7:14

"And Joseph sent, and called to him Jacob his father, and all his kindred, threescore and fifteen souls." — Acts 7:14 (ASV)

When he says that Jacob came into Egypt with seventy-five souls, it does not agree with the words of Moses, for Moses mentions seventy only. Jerome thinks that Luke does not record, word for word, what Stephen had said, or that he took this number from the Greek translation of Moses (Genesis 46:27), either because he himself, being a proselyte, did not have knowledge of the Hebrew language, or because he would concede this to the Gentiles, who were accustomed to reading it this way.

Furthermore, it is uncertain whether the Greek interpreters intentionally set down this number, or whether it crept in afterward through negligence or mistake. The latter is quite plausible, since the Greeks used to write their numbers as letters. Augustine, in his 26th book of City of God (De Civitate Dei), thinks that Joseph’s nephews and relatives are included in this number; and so he thinks that the words went down signify all the time that Jacob lived.

But that conjecture cannot be accepted at all. For, in the meantime, the other patriarchs also had many children born to them. It seems likely to me that the Seventy Interpreters accurately translated what was in Moses. And we cannot say that they were deceived, since in Deuteronomy 10, where this number is repeated, they agree with Moses—at least as that passage was undoubtedly read in the time of Jerome, for the copies printed today have it differently.

Therefore, I think that this difference arose from the error of the scribes who copied the books. It was not a matter of such importance that Luke should have troubled the Gentiles who were accustomed to the Greek reading. And it may be that he himself recorded the true number, and that someone incorrectly altered it based on that passage in Moses. For we know that those who handled the New Testament were ignorant of the Hebrew language, yet skilled in Greek.

Therefore, so that Stephen's words might agree with the passage in Moses, it is to be supposed that the incorrect number found in the Greek translation of Genesis was also inserted by them in this place. Concerning this, if anyone contends more stubbornly, let us allow him to be wise beyond measure.

Let us remember that it is not without reason that Paul forbids us to be too curious about genealogies. This very small number is intentionally stated, so that God's power may appear more plainly in the great expansion of that family line over a relatively short period. For such a small handful of men could not, by any ordinary human means of reproduction, grow to such an immense multitude as is recorded in Exodus 12:37, within two hundred and fifty years. We ought rather to consider the miracle that the Spirit commends to us in this passage, than to dwell long on a single letter by which the number is altered. Other questions arise from the rest of the context, and these are more difficult to answer.