Commentaire sur Le Deutéronome 2:6

תכרו — This is an expression denoting purchase. Similar is (Genesis 50:5; see Rashi thereon), “which I have bought (כריתי) for myself”, for thus in the coast cities do they use for "trading” the term כירה (Rosh Hashanah 26a).

YE SHALL PURCHASE FOOD OF THEM FOR MONEY. If you should desire to eat of the fruits of their land you should not take it from them except for the full price¹²⁹Ibid., 23:9. at their pleasure, this being the sense of the word me’itam (of them) [purchase food ‘of them,’ i.e., with their consent]. Also you shall not drink water of them at all, except for money with their consent.

אכל תשברו מאתם, “You may purchase food from them;” Our author understands these words as a question: “Do you need to purchase food from them? Are you short of water?” In other words: “seeing that all your needs are taken care of why would you be interested to set foot on the soil of these people?” This is also why the Torah immediately continuous with: “for the Lord your G’d has blessed you in all your handiwork during all these forty years.”

V. 6. אכל תשברו, nicht mehr als für den augenblicklichen Bedarf (siehe Bereschit 41, 56). וגם מים, selbst Wasser, das doch seiner Natur nach mehr der freien Natur, als der Menschenbotmässigkeit angehört. (תכרו siehe Bereschit S. 49, 5)