Chasidut zu Bereschit 41:45

Exodus 1,6. “and Joseph had meanwhile been in Egypt ‎already.” We need to examine why the Torah had to repeat ‎the word ‎במצרים‎, “in Egypt,” when it would have sufficed to ‎simply write ‎ויוסף היה שם‎, “while Joseph had already been there.” ‎Perhaps the Torah wanted to stress that during all the years that ‎Joseph had been in Egypt without the moral support of his family ‎he had not changed his name (although Pharaoh had given him ‎an Egyptian title, i.e. ‎צפנת פענח‎). He himself used to refer to ‎himself by his Jewish name. Even Pharaoh realized this when ‎during the early days of the famine he had instructed the people ‎to turn to Joseph for help, i.e. ‎לכו אל יוסף אשר יאמר לכם תעשו‎, ‎‎“what Joseph will tell you, you are to do.” (Compare Bereshit ‎Rabbah 20 slightly differently wording.)‎

Genesis 39,17. “your servant has done to me unspeakable ‎things.” According to Rashi the conversation described ‎in the Torah here occurred while Potiphar and his wife were ‎having marital relations. At first glance, this appears somewhat ‎difficult to understand as in Genesis 41,45 when the Torah ‎reports that Pharaoh gave Joseph as a wife the daughter of ‎Potiphar, Rashi points out that Potiphar was impotent, as a ‎penalty for having desired to use Joseph for homosexual ‎practices, and that Ossnas was not his biological daughter. We ‎must therefore assume that the attempted seduction of Joseph ‎occurred earlier. If so, why did he become impotent only at a later ‎stage?‎
Actually, the Almighty Who performs wonderful deeds ‎completely unassisted, arranges events in such a way that the ‎wicked will commit fatal errors, as we know from Job 12,23 ‎משגיא ‏לגויים ויאבדם‎, “He leads (wicked) nations astray and causes their ‎destruction.” If G’d had made Potiphar impotent earlier, he could ‎not have believed his wife when she described that Joseph had ‎engaged in similar activities to the ones practiced by her husband ‎during marital intercourse. In addition to this, the Torah testified ‎that Potiphar was aware of and admired Joseph’s absolute loyalty ‎and sincerity, as we know from 39,3 and 4. The Torah sometimes ‎shows us how G’d, on occasion, lets a wicked person enjoy a ‎degree of success even when they are in the process harming the ‎righteous, so that the righteous has a chance to become stronger ‎in his faith in G’d. When this happens the wicked interprets it as ‎proof that G’d approves of what he has been doing, whereas in ‎fact G’d is only preparing the downfall of the wicked. Ultimately, ‎in retrospect, G’d will be seen as having misled the wicked, as per ‎Job 12,23.‎