From the time that he made him overseer in his house and over all that he had, YHWH blessed the Egyptian's house for Joseph's sake; the blessing of YHWH was on all that he had, in house and field.
#genesis 39:5 #vayeshev

God blessed Potiphar even though he kept Joseph as a slave. Why did God bless him for that? Kindness is like water. Its form adjusts to the vessel in which it is placed.