John Calvin on Exodus 4:19

19. And the Lord said Lat., “had said.” unto Moses Some connect this sentence with what follows, as if God had spoken to his servant after permission to return had been given him by his father-in-law; but my opinion rather is, that what had before been omitted is here inserted out of its place. Such repetition is frequent in the Scriptures. “And the Lord said unto Moses in Midian, i e., at a different time from that when he appeared to him in the wilderness at Mount Sinai. Things are not always recorded in the sacred writings in the order in which they happened.” — Rosenmuller in loco Moses, therefore, adds to what he had already said, that the fear of danger was removed, since God had testified that the recollection of his having slain the Egyptian had ceased. For this would have been a stumblingblock at the very outset, if Moses had supposed that this accusation would have met him; not because his conscience smote him before God, but because he would have been rejected by the perverse judgments of men. Therefore, on this point, also, God provides against his fear, assuring him that the enemies were dead who had plotted against his life. And, perhaps, he now particularly notices this, because in asking for leave to depart, he could safely speak of it; for it is probable that Jethro, before he had married his daughter to an unknown foreigner, had demanded the cause of his exile; since it was easy to conjecture by his wandering in the Desert, that he had been expelled from his country. Having then confessed that he fled from the wrath of the king, he now says that he is recalled by divine revelation, and that a safe return is promised him. Nor is he guilty of falsehood; for, amongst other things, God had promised him that no danger awaited him from his former enemies.