Parashas Vayeishev · Passuk 37:3
Now Yisrael loved Yosef more than all his sons, because he was the son of his old age; and he made him a coat of many colors.
Torah Temimah points to Shabbos 10b.
English: Rav Chama bar Gurya said in the name of Rav: A person should never single out one of his sons from among the others, for because of the weight of two selaim of fine wool that Yaakov made for Yosef more than for his other sons, his brothers became jealous of him and the matter rolled on until our fathers went down to Egypt.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The coat of many colors is read as the concrete cause of the jealousy that led to the Egyptian exile.
A parent must not favor one child over the others even in a small matter. Yaakov’s gift of the special coat to Yosef aroused the brothers’ jealousy and set in motion the chain of events that brought the family down to Egypt.