Variantly: "Torah was commanded to us by Moses": It is not from Moses alone that we hold the Torah; for our fathers, too, acquired it, viz. (Devarim, Ibid.) "the inheritance of the congregation of Jacob." This tells me (only) of an inheritance for the sons of kings. Whence do I derive the same for the sons of non-kings? From (Devarim. 29:9) "You are standing this day, all of you, etc." Variantly: Do not read it "morashah" ("inheritance"), but me'orasah" ("betrothed"), the Torah being betrothed to Israel, and (it is forbidden) to the gentiiles as (is) a married woman.
Similarly, (Mishlei 6:27-29) "Will a man draw forth fire into his lap, and his clothes not be burned? Will a man walk on coals and his feet not be scorched? So, he who comes to his friend's wife. No one who touches her shall go clean." Thus "the betrothed of the congregation of Jacob."