Chasidut על מנחות 68:1

Genesis ‎18,5. “let me take a piece of bread so that you can refresh ‎yourselves,……he presented it to them and they ate.” The true ‎meaning of this verse has been best explained by the Or ‎Hachayim, according to whom even the highest ranking angel, ‎Michael is on occasion referred to as “High Priest,” whereas on ‎other occasions he is known by another name. [Not in my edition ‎of the ‎אור החיים‎. Ed.] The point of this is to alert us to the fact ‎that the standing, or even existence, of the angels in the celestial ‎spheres, is affected by the mitzvah performance of the ‎Israelites in the terrestrial part of the universe. When Israel is ‎meticulous in the performance of G’d’s Torah, then the most ‎senior of the angels in the celestial spheres assumes the title: ‎‎“High Priest.” When Avraham spoke about a ‎פת לחם‎, instead of ‎merely ‎פת‎, bread, he alludes to both the written and the oral ‎Torah. The word ‎פת‎ refers to the written Torah, whereas the word ‎לחם‎ refers to the oral Torah. The word ‎לחם‎ in psalms 78,25 i.e. ‎לחם אבירים‎, is an allusion to the Torah. According to the Talmud ‎‎Menachot 34, the word ‎פת‎ amongst the Africans means ‎‎“two.” [The latter half of the word: ‎טוטפת‎. Ed.] The word is used ‎as an allusion to Torah also in Proverbs 9,5, ‎לכו לחמו בלחמי‎, “come ‎and partake of My bread.” [Compare Alshich, pages 171-172, my ‎translation of Proverbs. Ed.] When Avraham is now described as ‎serving the angels, we may see in this the reward both for ‎Avraham‘s having performed the circumcision on himself, as well ‎as reward for the angels, their being hosted by a person of ‎Avraham’s standing. [Perhaps the mitzvah of hospitality ‎shown the angels by Lot in the following chapter was a factor in ‎his being saved, whereas his wife was not. Ed.] When Avraham, in ‎verse 8, is described as standing next to the angels while the latter ‎were seated while eating, the “tree” mentioned in that verse may ‎be a reference to the tree described as “tree of life” in Proverbs ‎‎3,18, i.e. an allusion to the Torah.