The Insights to the Daf for Daf 46 says-
>>The RAMBAN and RASHBA explain that the Milah the Jewish people performed in Mitzrayim was not merely to permit them to eat the Korban Pesach. Moshe Rabeinu told them to perform Milah in order to accept the Mitzvos upon themselves and to be "Nichnas Tachas Kanfei ha'Shechinah" -- to become the nation of Hash-m. That is what the Mechilta (Shemos 12:6) means when it says that at the time of the Exodus the Jews lacked the merit of Mitzvos, and therefore Hash-m gave them two Mitzvos to perform -- Milah and the Korban Pesach (Mechilta Shemos 12:6). Hash-m gave these Mitzvos to the Jewish people in order to make them His chosen nation.<<
At what point did the Jews become the Jewish People - Layl Pesach, Kriyas Yam Suf, when Moshe sprinkled the blood on them, or at Har Sinai
Akiva Lane, Ramat Bet Shemesh, Israel
The Gemara in Chulin 101b says that the Jews became known as Bnei Yisrael at Sinai. Rashi in Avodah Zarah (51a DH li'Vnei No'ach) says this means until the Torah was given. (See also Rashi Zevachim 116a DH l'Kol Avodah Zara 3a DH Nimrod Chulin 100b DH Deika Nami.)
Tosfos on the Gemara in Chulin (101b DH l'Achar) explains that even though Hash-m did indeed change Yakov's name to Yisrael, even so as far as Mitzvos are concerned the name Bnei Yisrael only applies after Matan Torah.
The Ramban in his Perush on the Torah at the end of Parshas Emor (24:10) says that from when Avraham entered into the Bris with Hash-m he is considered Yisrael and not a Ben No'ach. (Rebbi Akiva Eiger in Ksav v'Chosem #60 explains that the Ramban is referring to Bris Milah, not the Bris Bein ha'Besarim). This would appear to be a contradiction to the Gemara in Chulin 101b quoted above.
We may reconcile the Ramban with the Gemara according to the opinion of the Brisker Rav (Chidushei ha'Griz Yuma 28b and Sotah 8b) that the Avos were Yisrael but were not called Yisrael for Mitzvos until Matan Torah.
See also Parashas Derachim (Drushim 1 and 2) for a lengthy discussion of this topic, and Kovetz Shiurim Bava Basra (54).
Regards,
Dov Freedman