TT #40 · Parashas Vayechi · Passuk 49:14
Issachar is a large-boned ass, Couching down between the sheep-folds. And he saw a resting-place, that it was good, and the land, that it was pleasant; and he bent his shoulder to bear, and became a servant under taskwork.
Torah Temimah cites Niddah 31a.
English: What is the meaning of “and he lay with her that night”? It teaches that the Holy One, blessed be He, assisted in that act, as it is stated, “Issachar is a strong-boned donkey”: the donkey caused Issachar to be born.
Midrashic reading linking the word “hu” with the birth of Issachar; the citation is the Torah Temimah cross-reference for this second unit.
The Torah Temimah note connects the wording of Genesis 30:16 with “Issachar is a strong-boned donkey,” teaching that the circumstances leading to Issachar’s birth were divinely assisted.