From the article:
Calvin also indicates that he was aware of trivial inaccuracies in scripture such as the seventy-fiver rather that seventy people in Acts 7:14 and the posture of Jacob in Hebrews 11:21.
How man people were with Jacob?
Acts 7:14: And Joseph sent and summoned Jacob his father and all his kindred, seventy-five persons in all.
John Calvin said:
Whereas he saith that Jacob came into Egypt with seventy-five souls, it agreeth not with the words of Moses; for Moses maketh mention of seventy only. Jerome thinketh that Luke setteth not down, word for word, those things which Stephen had spoken, or that he took this number out of the Greek translation of Moses, (Genesis 46:27,) either because he himself, being a proselyte, had not the knowledge of the Hebrew tongue, or because he would grant the Gentiles this, who used to read it thus. Furthermore, it is uncertain whether the Greek interpreters set down this number of set purpose, or whether it crop [crept] in afterward through negligence, [mistake;] which (I mean the latter) might well be, forasmuch as the Grecians used to set down their numbers in letters. Augustine, in his 26th book of City of God, [De Civitate Dei,] thinketh that Joseph’s nephews and kinsmen are comprehended in this number; and so he thinketh that the words went down doth signify all that time which Jacob lived. But that conjecture can by no means be received. For, in the mean space, the other patriarchs also had many children born to them. This seemeth to me a thing like to be true, that the Seventy Interpreters did translate that truly which was in Moses. And we cannot say that they were deceived; forasmuch as [in] Deuteronomy 10, where this number is repeated, they agree with Moses, at least as that place was read without all doubt in the time of Jerome; for those copies which are printed at this day have it otherwise. Therefore, I think that this difference came through the error of the writers which wrote out the books. And it was a matter of no such weight, for which Luke ought to have troubled the Gentiles which were accustomed with the Greek reading. And it may be that he himself did put down the true number; and that some man did correct the same amiss out of that place of Moses. For we know that those which had the New Testament in hand were ignorant of the Hebrew tongue, yet skillful in the Greek,
Therefore, to the end [that] the words of Stephen might agree with the place of Moses, it is to be thought that that false number which was found in the Greek translation of Genesis was by them put in also in this place; concerning which, if any man contend more stubbornly, let us suffer him to be wise without measure. Let us remember that it is not without cause that Paul doth forbid us to be too curious about genealogies. This, so small a number, is purposely expressed, to the end the power of God may the more plainly appear, in so great an enlarging of that kindred, which was of no long continuance. For such a small handful of men could not, by any human manner of engendering, grow to such an infinite multitude as is recorded in Exodus 12:37, within two hundred and fifty years. We ought rather to weigh the miracle which the Spirit commendeth unto us in this place, than to stand long about one letter, whereby the number is altered. There arise other questions (and those which are more hard to be answered) out of the rest of the text, [context.]
From the ESV study bible notes on Acts 7:14 says:
When Stephen cites the number of Jacob's kindred at seventy-five, he is following the Septuagint rather than Hebrew text for Ex. 1:5, which follows a different calculation and arrives at the number 70. The different texts were apparently based on different decisions regarding whether to include Jacob and his wife and the additional descendants born to Ephraim and Manasseh in Egypt.
The posture of Jacob
Hebrews 11:21: By faith Jacob, when dying, blessed each of the sons of Joseph, bowing in worship over the head of his staff.
This is one of those places from which we may conclude that the points were not formerly used by the Hebrews; for the Greek translators could not have made such a mistake as to put staff here for a bed, if the mode of writing was then the same as now. No doubt Moses spoke of the head of his couch, when he said על ראש המטה but the Greek translators rendered the words, “On the top of his staff” as though the last word was written, mathaeh. The Apostle hesitated not to apply to his purpose what was commonly received: he was indeed writing to the Jews; but they who were dispersed into various countries, had changed their own language for the Greek. And we know that the Apostles were not so scrupulous in this respect, as not to accommodate themselves to the unlearned, who had as yet need of milk; and in this there is no danger, provided readers are ever brought back to the pure and original text of Scripture. But, in reality, the difference is but little; for the main thing was, that Jacob worshipped, which was an evidence of his gratitude. He was therefore led by faith to submit himself to his son.
The English translation above has the footnote:
Various have been the opinions on this clause. It is clear that the words here refer to a time different from that mentioned in Genesis 47:31. They are connected in Genesis with the oath which Joseph made to his father to bury him in Canaan; but here with the blessing of his sons recorded in the following chapter, 48:15-16. These were two separate transactions, and the words only occur in the first; and it seems from the words of the Apostle, that the act and position of Jacob were also the same in the second instance.
The points are of no authority; and the Apostle adopted the Septuagint version, and thus sanctioned it: and there is no reason to dispute that sanction. David is said to worship upon his bed, (1 Kings 1:47;) but the word for bed there is different. All the difficulty here vanishes, if we throw aside as we ought to do, the points. The word for worship in Hebrew means to prostrate one’s self on the ground, the humblest mode of adoration; but it is used also to designate merely an act of worship. See 1 Samuel 1:3; 2 Kings 5:5, 18. The reason why Jacob is said to have worshipped unable to adopt the usual posture.