Thurs Nazir 5

R' Masna says the reason why one shouldn't shave fro his Nazirus on the thirtieth day (which would be permitted, because he holds part of the day is like the complete day) because L'chatchila we don't rely on part of a day is likethe whole day (as we'll explain later.)

According to Bar Pada that says that the whole Nazirus is only 29 days (full days, since he doesn't hold that part of a day is like a full day.) that we don't L'chatchila shave on the 30th because a Gezaira if he would specifically say he's a Nazir for 30 full days.

Tosfos points out that Bar Pada doesn't need to say 30 full days so that he can't shave on the 30th day. As long as he says for 30 days, we know he cannot shave the whole thirtieth day, since he doesn't hold of part of a day is like a whole day. Only to R' Masna, the reason he can't shave on day 30 perhaps he'll say he's a Nazir a full 30 days. Without saying it's full, he would be able to shave on day 30, because he holds part of a day is like the whole day unless you specifically make a condition that the days are full.

Blast your way into Elul Zman:

"Gemara and Tosfos"

Try First Amud of Perek Free

tosfos.ecwid.com