Deuteronomy 2:6

Ye shall purchase … ye shall buy Heb. shabar, literally to deal in grain(Genesis 41:57, etc.), but also victuals (Genesis 42:7), and karah, to buy, only here Hosea 3:2 and in Job. JE, Numbers 20:19: if we drink of thy water, I and my cattle, then I will give the price thereof. To-day nomad Arabs, who winter in the warm -Arabah, seek to cross Mt Se-îr with their cattle by one or other of several passes to summer pastures on the E. plateau and the wilderness of Moab. The passes are easily defended by the peasants of the Mt, who seek to prevent them; yet they are glad when the nomads travel on the edge of the desert, for then they can barter with them (Musil, Edom, ii. 15). Where there are no brooks but only cisterns or easily guarded springs, the peasant possessors of these will refuse to sell even small draughts to one or two passing travellers, as the writer has more than once experienced; cp. Musil, Moab, 132. It is conceivable how water would be still more jealously guarded from a large caravan or host, with appetites sufficient to exhaust the cisterns. It is implied in Deuteronomy 2:29 that Edom agreed to supply food and water.