5 And it came to pass from the time that he had made him overseer in his house, and over all that he had, that the Lord blessed the Egyptian’s house for Joseph’s sake; and the blessing of the Lord was upon all that he had in the house, and in the field. 6 And he left all that he had in Joseph’s hand; and he knew not ought he had, save the bread which he did eat. And Joseph was a goodly person, and well favoured.
I don’t know much about the structure of servants in an ancient Egyptian household, but I think it seems incredible that a youth of seventeen years, brought in as a slave from a foreign land, would climb to overseer in Potiphar’s house. We do not know how exactly what length of time transpired before Potiphar trusted Joseph completely, but I imagine the process was expedited by the fact that Joseph’s works prospered beyond normal human capability, due to the intervention of the Lord.
In any case, eventually Potiphar depended so fully on Joseph that he did not even know what his own belongings were. He put it all under Joseph’s hand and trusted that the young man would not cheat him. All that remained for Potiphar was to reap the blessings of it, the bread that was served to his table.
But there is a difference between being the man that the Lord blesses and being the man who profits from the blessed one. Potiphar is in the same situation as Laban, who similarly reaped the reward of having a man of God, Jacob, under his employ. But also like Laban, Potiphar will not keep his good-luck-charm forever. He will have God’s blessing upon his household only as long as Joseph is present. Joseph, on the other hand, will keep the providence of the Lord wherever he goes.