C. F. Keil and Franz Delitzsch on Genesis 25:27-28

Gen 25:27-28

Esau became “a cunning hunter, a man of the field,” i.e., a man wandering about in the fields. He was his father’s favourite, for “venison was in his mouth,” i.e., he was fond of it. But Jacob was תּם אישׁ, “a pious man” (Luther); תּם, integer, denotes here a disposition that finds pleasure in the quiet life of home. אהלים ישׁב, not dwelling in tents, but sitting in the tents, in contrast with the wild hunter’s life led by his brother; hence he was his mother’s favourite.