Reader! do not overlook in this verse, that this captain of the guard must have been Potiphar, Genesis 39:1. Whether by this time Joseph's master had begun to believe Joseph was innocent doth not appear, but yet it should seem so, in that he committed to his care those state prisoners.
Related Commentaries of Genesis 40:2
Genesis 40:2-4
2 And Pharaoh was wroth against two of his officers, against the chief of the butlers, and against the chief of the bakers.
3 And he put them in ward in the house of the captain of the guard, into the prison, the place where Joseph was bound.
4 And the captain of the guard charged Joseph with them, and he served them: and they continued a season in ward.