Genesis 40:4

“And the captain of the guard charged Joseph with them, etc.] Committed them to his care and custody, he being very probably recommended to him by the keeper of the prison for his prudence and fidelity; and if it was Potiphar, he knew his character full well, and might be now reconciled unto him, as having had a more full and clear account of the affair between him and his wife from the keeper of the prison; and therefore though he might not think fit for his own and his wife’s reputation to remove him from prison as yet, nevertheless might be inclined to do him what service he could, as well as honour, as this was, to have two such state prisoners committed to his care. Some render it, “he…”

“The captain of the guard charged Joseph with them--not the keeper, though he was most favorably disposed; but Potiphar himself, who, it would seem, was by this time satisfied of the perfect innocence of the young Hebrew; though, probably, to prevent the exposure of his family, he deemed it prudent to detain him in confinement (see Psa 37:5). They continued a season in ward--literally, "days," how long, is uncertain; but as they were called to account on the king's birthday, it has been supposed that their offense had been committed on the preceding anniversary [CALVIN].”

“- Joseph in Prison An uncomplaining patience and an unhesitating hopefulness keep the breast of Joseph in calm tranquillity. There is a God above, and that God is with him. His soul swerves not from this feeling. Meanwhile, new and distinguished prisoners are introduced into his place of confinement. Genesis 40:1-4 The chief butler and chief baker, high officials in Pharaoh’s court, come under the displeasure of their sovereign. “In the house of the captain of the guards.” It appears that this officer’s establishment contained the keep in which Joseph and these criminals were confined. “Charged Joseph with them.” As Joseph was his slave, and these were state prisoners, he appointed him to…”