Acts 13:21 - Matthew Poole's English Annotations on the Holy Bible

Their great sin in desiring a king was, because by that desire they rejected God, who had at that very time a prophet (Samuel) by whom he governed them, 1 Samuel 8:7, 1 Samuel 10:19. They had been under a theocracy ever since they came out of Egypt, their laws and their governors being appointed by God; had their condition been as that of other nations, their desire had not been a provocation. These words, by the space of forty years, are to be joined with the foregoing verse, and the other foregoing words in the verse read with a parenthesis: and thus they show how long Samuel the prophet (as he is here called) exercised his prophetical office, which was the space here mentioned, partly before Saul was anointed king, and in part afterward; in which, as another Moses, he cared for, and went in and out before, the people of God, the like space of forty years. This computation of St. Paul might also agree more with the Septuagint, and be according to the then current account, which (not being of more consequence) St. Paul would not controvert at this time, having greater matters to speak of unto them.