1)
When will the Nasi come "Derech Ulam ha'Sha'ar"?
1.
Rashi: On Rosh Chodesh and Shabbos Bereishis 1 , when Yisrael are not commanded about Re'iyah (to be seen in the Azarah), and he comes to bow.
2)
What is the Chidush "uv'Darko Yetzei"?
1.
Rashi: He is not commanded to make the Azarah a shortcut (to leave in the opposite side of where he entered). However, during the Mo'adim, it says "Yera'eh Chol Zechurecha" (Devarim 16:16) ? he must make it a shortcut, like the rest of the nation ? "b'Socham b'Vo'am Yavo uv'Tzeisam Yetze'u" (10). Radak ? perhaps also the rest of the nation do not make it a shortcut on Shabbos and Rosh Chodesh. Rather, they leave from where they entered.
