The Torah portion of Behar begins by saying:1 “G‑d spoke to Moshe on Mount Sinai….” It then details the laws of Shemitah , the Sabbatical year. Rashi , quoting Toras Kohanim asks:2 “What [particularly] has Shemitah to do with Mount Sinai; all the commandments were given on Sinai.!” He answers: “Just as the general, specific, and most minutely detailed laws of Shemitah were related at Sinai, so too, all [the mitzvos] were related, generally, specifically and most minutely at Sinai.”

This comment is in accord with the opinion of Rabbi Akiva that “The general as well as the specific laws were given at Sinai”3 ; it negates the opinion of Rabbi Yishmael, who maintains that only “the general principles were given at Sinai,” and “the specific laws were related in the Tabernacle.”4

Why do Rabbis Akiva and Yishmael disagree; what lies at the root of their argument?

R. Yishmael, who was a High Priest, served G‑d in the priestly manner of “holy of holies”5 — the service of the completely righteous tzaddikim, while R. Akiva, who descended from proselytes, served in the manner of penitents.6

This explains why R. Akiva said concerning the self-sacrificial manner of service known as mesirus nefesh ,7 “All my days I agonized…. when will the opportunity [for actual mesirus nefesh] present itself so that I will be able to perform it?”

The service of tzaddikim is such that the feeling of mesirus nefesh is required only at the beginning of the day, at the time of the recital of the Shema ; during the rest of the day they go about their service of Torah and mitzvos with but a remnant of that emotion.

However, he whose service is in the manner of repentance — a manner of spiritual service that transcends all limitations — will find himself in the state of mesirus nefesh “all his days ,” i.e., the whole day through.

It was this difference in approach to spiritual service that caused R. Yishmael to disagree regarding whether the specific laws were given on Sinai or in the Tabernacle:

The difference between Sinai and the Tabernacle was that the Tabernacle was constructed in a most orderly fashion, with separations between its various parts, with a progression from courtyard to Sanctuary, and within the Sanctuary itself, from the holy to the Holy of Holies. As such, it symbolized orderly and progressive spiritual service.

Sinai, however, was in the desert. It was not a place of order and settlement. It was thus representative of spiritual service that transcends order — transcendent mesirus nefesh.

Herein lies the basis of their disagreement: For the service of tzaddikim — R. Yishmael — it suffices that the general principles were given at Sinai. I.e., when we speak of mitzvos in their general state (i.e. the underlying foundation of all mitzvos) we presuppose the state of Sinai — mesirus nefesh. However, when we speak of their detailed and specific fulfillment, the orderly manner of service symbolized by the Sanctuary is required.

R. Akiva, however — displaying the service of penitence that transcends orderly progression — maintains that it is possible as well as necessary to experience mesirus nefesh — Sinai — even as one goes about performing the specific details of mitzvos , and indeed during all of one’s activities.

Based on Likkutei Sichos Vol. XVII pp. 276-284.