How does "Eleh ha'Devarim" - hint to 39 Melachos?

Rashi: Devarim (plural) teaches two. The 'Hei' teaches one more. The Gematri'a of Eleh is 36.

It says "Eleh ha'Devarim Asher Tzivah Hash-m La'asos." How can we learn from here the Melachos that we may not do?

Rav Elyashiv: Hash-m commanded Moshe to gather multitudes and teach to them what is permitted and what is forbidden (Yalkut Shimoni. va'Yakhel, brought in Beis Yosef (OC 290). It was a general command to teach Torah laws. Daf Al ha'Daf citing Zechor l'Avraham (5764 p.773) - they taught laws of Shabbos on Shabbos, and laws of each Yom Tov on its day. Sefas Emes (Megilah 4a) - Shabbos is written at the beginning of the Mo'adim. Surely Moshe's command to engage in Halachos of each Mo'ed on the day applies to Shabbos, and all the more so according to Tosfos, that we expound 30 days before Yom Tov. (NOTE: Without Tosfos' Chidush, can we learn from an obligation to engage in Hilchos Yom Tov seven days a year, to engage in Hilchos Shabbos 50 times? - PF)