don't stock up for the road

Bnei Yisrael is told that they are not allowed to wage war against Eisav, but can only pass through their land.  When they do so, they should buy food and drink from the local stores (2:6-7):

 אֹ֣כֶל תִּשְׁבְּר֧וּ מֵֽאִתָּ֛ם בַּכֶּ֖סֶף וַאֲכַלְתֶּ֑ם וְגַם־מַ֜יִם תִּכְר֧וּ מֵאִתָּ֛ם בַּכֶּ֖סֶף וּשְׁתִיתֶֽם׃

כִּי֩ ה׳ אֱלֹקיךָ בֵּֽרַכְךָ֗ בְּכֹל֙ מַעֲשֵׂ֣ה יָדֶ֔ךָ יָדַ֣ע לֶכְתְּךָ֔ אֶת־הַמִּדְבָּ֥ר הַגָּדֹ֖ל הַזֶּ֑ה זֶ֣ה׀ אַרְבָּעִ֣ים שָׁנָ֗ה ה׳ אֱלֹקיךָ֙ עִמָּ֔ךְ לֹ֥א חָסַ֖רְתָּ דָּבָֽר׃

What does כִּי֩ ה׳ אֱלֹקיךָ בֵּֽרַכְךָ֗ בְּכֹל֙ מַעֲשֵׂ֣ה יָדֶ֔ךָ have to do with buying food?  Rashi explains that Moshe was telling the people to pay full price and not look for discounts, coupons, etc. לפיכך לא תכפו את טובתי להראות כאילו אתם עניים, אלא הראו עצמיכם עשירים.  You should not let Eisav think that you are poor and can't afford it.  On the contrary, show them that Hashem has blessed you and that the price is no concern.  Unlike Ibn Ezra and Rashbam who explain these pesukim as a reshus, a matir -- if you want to buy from them, you can, but if not, not -- Netziv explains that it is a command, אכל תשברו – בלשון צווי, because in doing so you are advertising Hashem's bracha.

HaKsav v'haKabbalah notes that the words  וַאֲכַלְתֶּ֑ם and וּשְׁתִיתֶֽם in the first pasuk seem to be extraneous.  You obviously buy food to eat; you buy water to drink.  Why does the pasuk have to spell it out for us?  He answers that the Moshe was telling Bnei Yisrael that whatever food they bought when passing through Eisav's land should be eaten there, on the spot, and the same with whatever drink they bought.  There was no need to ask for a doggie bag or stock up on supplies for the road.  My wife suggested that based on this, you can read the connection to the next pasuk a little differently.  כִּי֩ ה׳ אֱלֹקיךָ בֵּֽרַכְךָ֗ ... לֹ֥א חָסַ֖רְתָּ דָּבָֽר׃  You know that for 40 years Hashem took care of you and you can bank on Him.  Therefore, don't clear the shelves off the supermarkets in Eisav's lands because you are worried about tommorow's meal.  Show them your bitachon.