Genesis 39:19-21

"And it came to pass when his master heard the words of his wife, which she spake unto him, saying, After this manner did thy servant to me; that his wrath was kindled. And Joseph's master took him, and put him into prison, the place where the king's prisoners were bound: and he was there in prison. But Jehovah was with Joseph, and showed kindness unto him, and gave him favor in the sight of the keeper of the prison."

"His master's wrath was kindled ..." The tradition handed down through Josephus is that Potiphar believed his wife's accusation, and that even after the events of this chapter, spoke highly of her as a woman of virtue. Despite this, however, there would appear to be a great deal of doubt about it. First, the sentence executed upon Joseph was "hardly expected for a slave taken for attempted rape of his master's wife,"[17] the death penalty being usual in such cases. There is also the fact that Potiphar evidently placed Joseph in a prison under his own jurisdiction, which also he did without any kind of trial, assigning the penalty under his own authority. From these considerations, many scholars have concluded that perhaps Potiphar accepted the truth of his wife's charges against Joseph with something less than total belief.

Why then, was Joseph imprisoned at all? It would have been necessary in order for Potiphar to make an example of Joseph to the other slaves and to prevent social repercussions of all kinds. What kind of imprisonment was it? Not long afterward, when Joseph's favor with the deputy captain of the guard had been established, his lot was evidently quite tolerable; but, at first, the imprisonment was extremely rigorous. Psalms 105:18 has this:

He (God) sent a man before them (Israel); Joseph was sold for a servant: His feet they hurt with fetters: He laid in chains of iron.

Significantly, an alternate reading for the fourth line of this quotation is rendered in one of the Targums as, "The iron entered into his soul."[18] What caused the drastic change that followed? As to what did it, we do not know, but as to who did it, we are certain. The answer is given in this passage, "Jehovah was with Joseph and showed kindness unto him." It could easily have been that God sent Potiphar a dream, as God did for Pharaoh in the very next chapter, or it might have been some other development. One thing seems likely enough, and that is that Potiphar's deputy would not have so drastically alleviated Joseph's punishment without Potiphar's consent.

"The keeper of the prison ..." here, "was the governor or superintendent of the prison, and under Potiphar."[19]