Why are we strict during the 10 days of repentance?

Question

The lone halacha in Shulchan Aruch O.C. 603:

Even someone who is not careful about eating [pas akum], during the 10 days of repentance he must be careful.

Since the S.A. didn't mention stringencies of a higher caliber, I had always applied this specifically to cases like pas akum where being strict was preferable even according to the more lenient approach. I assumed that being strict in permitted vs forbidden cases would put your past actions in a bad light.

I saw recently that the Aruch haShulchan takes a similar approach, but his logic is that acting strict in permitted vs forbidden cases is like accepting the strict approach for the future.

I have heard many prominent Rabbis tell their congregants/students to be strict during these days. As an example, even if you don't normally drink chalav yisrael...

My question is: Is there a source that applies this law to permissible/forbidden cases? If the halacha is applied broadly, why did the S.A (or the Tur) use pas akum instead of more serious issues?

Answer 1

The Tur (Orach Chayyim 402) quotes the Yerushalmi (Shabbat 1:3) with a comment of the Raavyah.

The Yerushalmi reads:
רבי חייא רובא מפקד לרב אין את יכול מיכול כל שתא חולין בטהרה אכול. ואם לאו תהא אכילת שבעה יומין מן שתא.‏

(Roughly, The great Rabbi Hiyya commanded Rav, if you can eat ordinary food in purity all year long, eat. And if not, eat [in purity] seven days of the year.)

The Yerushalmi there continues with a t'shuvah-related statement by Rabbi Pinchas ben Yair.

The Raavyah comments (Siman 529):
וקבלתי שאלו שבעה ימים הם שבעה ימים שבין ראש השנה ליום הכיפורים:‏

(And I received a tradition, that these are the seven days between Rosh Hashanah and Yom Hakippurim. [See the footnotes in the linked edition for more sources.])

The Tur concludes that the custom in Ashkenaz is not to eat non-Jews' bread during the aseret y'mei t'shuvah, based on this. The Beit Yosef says that the sources are the Rosh, Mordechai, and Tashbetz (but I have not seen them inside).

The Beit Yosef further quotes the Tashbetz as disagreeing with the conclusion, because eating in purity is not forbidden, but if one is strict about non-Jews' bread now, that would be binding for the future (like the Aruch Hashulchan's position). However, the Beit Yosef disagrees with the disagreement, since the question of permitted/forbidden here is one of custom, if one wants to be strict only for these days, clearly that is not binding for the whole year.

Answer 2

Yes, there is a source extending this to being strict in other areas: Levush O.C. 603:1 writes that extra stringencies will remind us to be in a state of teshuvah. If that is the case, then the Tur must have merely picked this example (along with eating chullin b'taharah) because of convenience.

The Chayei Adam 143:1 and Kitzur Shulchan Aruch 130:2 write that because God is more merciful than 'necessary' during this time period, we should respond by keeping stringencies which we wouldn't normally consider to be necessary. Thus, this is a good example of something that the Tur doesn't really consider to be in dispute or require a heter, but is still a "real thing," considering that the Sages did prohibit it and haven't revoked it completely. I'm not sure what else would fit into this category

Rabbi Netanel Wiederblank suggested, based on Ramban, that being careful about pas yisrael was a custom of talmidei chachamim, and so we want to act like talmidei chachamim at this time. Rabbi Sobolofsky offered another possibility that because the decree for pas akum was rescinded only because it would be impossible to keep all year long (according to the Yerushalmi Avodah Zarah 2:8), it is not unreasonable to adhere to it for only ten days of the year.