Jamieson, Fausset and Brown on Genesis 37:12

12. his brethren went to feed their father's flock in Shechem--The vale of Shechem was, from the earliest mention of Canaan, blest with extraordinary abundance of water. Therefore did the sons of Jacob go from Hebron to this place, though it must have cost them near twenty hours' travelling--that is, at the shepherd rate, a little more than fifty miles. But the herbage there was so rich and nutritious that they thought it well worth the pains of so long a journey, to the neglect of the grazing district of Hebron [Van De Velde].