And the captain of the guard charged Joseph with them, and he served them: and they continued a season in ward.
The captain of the guard charged Joseph with them - not the keeper, though he was must favourably 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 Psalms 37:5). [The Septuagint, however, seems to have read a different Hebrew text here; for, instead of "the captain of the guard," they translate ho archidesmootees; Vulgate, custos carceris, the keeper of the prison.]
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 offence had been committed on the preceding anniversary (Calvin).