Sotah 37B

ארבע, ארבע וארבע הרי שמונה, שמונה ושמונה הרי שש עשרה. וכן בסיני, וכן בערבות מואב, שנאמר: ״אלה דברי הברית אשר צוה ה׳ את משה וגו׳, וכתיב: ״ושמרתם את דברי הברית הזאת וגו׳״. נמצא ארבעים ושמונה בריתות על כל מצוה ומצוה.

every mitzva contains 4 aspects. 4 general aspects and 4 specific aspects add up to 8. 8 blessings and 8 curses add up to 16. And so too at Mount Sinai, and so too at the plains of Moab, as it is stated: “These are the words of the covenant that YHWH commanded Moses to make with the children of Israel in the land of Moab, besides the covenant that He made with them in Horeb” (Deuteronomy 28:69). And it is written: “Observe therefore the words of this covenant” (Deuteronomy 29:8). It follows that between the 3 events where 16 covenants were made, God established 48 covenants for each and every mitzva.

רבי שמעון מוציא הר גריזים והר עיבל, ומכניס אהל מועד שבמדבר.

R' Shimon excludes Mount Gerizim and Mount Ebal from this list because only some of the mitzvot were mentioned there, and he includes instead the covenant at the Tent of Meeting in the desert.

ובפלוגתא דהני תנאי דתניא, רבי ישמעאל אומר: כללות נאמרו בסיני ופרטות באהל מועד. רבי עקיבא אומר: כללות ופרטות נאמרו בסיני, ונשנו באהל מועד, ונשתלשו בערבות מואב.

The Talmud explains: And it is in the dispute between these tanna’im that they disagree, as it is taught in a baraita (Tosefta 8:11): R' Yishmael says: General statements were said at Sinai, i.e., Moses received general mitzvot at Sinai, including the 10 Commandments. And the details of the mitzvot were explained to Moses at a later time in the Tent of Meeting. R' Akiva says: Both general statements and the details of mitzvot were said at Sinai, and later repeated in the Tent of Meeting, and reiterated a third time by Moses to the Jewish people in the plains of Moab. R' Shimon holds in accordance with his teacher, R' Akiva, and counts Mount Sinai and the Tent of Meeting as two distinct places where all of the mitzvot were given.