Rashi on Genesis 37:3/רש"י על בראשית ל״ז:ג׳

1בן זקנים THE SON OF HIS OLD AGE — because he was a wise son to him” — all that he had learnt from Shem and Eber he taught him (Genesis Rabbah 84:8). Another explanation of בן זקנים— his facial features were similar to his (Jacob’s) (Genesis Rabbah 84:8).

2פסים is a term for raiment of fine wool (Shabbat 10b). Similar is (Ester 1:6) כרפס “Fine linen and blue”. The same garment כתנת הפסים is mentioned (2 Samuel 13:18) in the story of Amnon and Tamar and we may therefore gather that it was made of very fine material. There is a Midrashic statement that in the word פסים we may find an allusion to all his misfortunes: he was sold to Potiphar (פוטיפר), to the merchants (סוחרים), to the Ishmaelites (ישמעאלים), and to the Midianites (מדינים) (Genesis Rabbah 84:8).