Вайикра 24:10 Галаха: Contemporary Halakhic Problems, Vol IV

Some latter-day authorities, including Parashat Derakhim, Derush 1, and R. Joseph Engel, Bet ha-Ozar, Ma'arekhet Alef, klal 1, marshal a variety of sources in support of the position that the Patriarchs, although not formally bound by the Sinaitic covenant, nevertheless enjoyed the status of full-fledged Jews for all other purposes.¹⁷The Brisker Rav, R. Yiẓḥhak Ze’ev ha-Levi Soloveichik, citing Ramban, Commentary on the Bible, Leviticus 24:10, argues that, since the days of Abraham, our ancestors enjoyed the status of Jews and hence, for them, Sabbath observance was not a “novel” religious observance. Nevertheless, prior to revelation at Sinai, they were not bound by the commandments. See Ḥiddushei Maran ha-Griz ha-Levi al Tanakh ve-Aggada, published in Batei ha-Leviyim (Jerusalem, 5746), no. 13, p. 7. If so, the problem is immediately resolved. However, even those authorities cite midrashic sources that serve to render the issue a matter of doubt or controversy.