This week the Ran sequed from Aharon’s reward to Aharon being included in the transmission of the mitzvah of Rosh Chodesh and starting the year in Nissan to what does it mean that the year starts in Nissan or in Tishrei. And how does one talk about the “start” of something that is a closed cycle to begin with?

From there we get to the dispute between Rabban Gamliel and Rabbi Yoshua about one particular Rosh Chodesh, and Beis Din’s authority to decide the month — even if their basis for the decision was an error in facts on the ground. Is this specifically a power over the calendar, or in deciding halakhah in general?

The text is available with footnotes at https://www.aishdas.org/kloiz/Derashos-haRan-derashah-3.pdf (starting at ¶ 18).

Or on Sefaria, beginning at https://www.sefaria.org/Derashot_HaRan.3.18

Derashos haRan is an explanation of the fundamentals of the Torah as explicated from texts in the Chumash. In the third derashah, the Ran discusses Moshe, Aharon, the nature of nevu’ah, Moshe’s special kind of nevu’ah,, the urim vetumim, and the first mitzvos given to the Jewish People — counting months from Nissan and of Pesach.