The Mishnah (Avodah Zarah 2:6) prohibits Jews from eating bread baked by a non-Jew. Based on the Gemara (Avodah Zarah 35 and Yerushalmi ad loc.), it is generally assumed that this prohibition only categorically applies to home-baked bread, but there are circumstances when bread from a non-Jewish bakery would be permissible, provided, of course, that the ingredients are kosher (see Shulhan Arukh Yoreh De’ah 112). While some Jews are strict to consume only pat yisra’el (bread prepared by a Jewish baker) all year long, it is generally accepted that this is a stringency, and not the strict Halakhah. However, Shulhan Arukh (Orah Hayyim 603:1) records the widespread practice that during the aseret yemei teshuvah, one should be especially stringent to consume only pat yisra’el. While surely this is the time of year for being scrupulous in one’s Mitzvah-observance, the particular focus on pat yisra’el is not immediately obvious. To better understand this custom, we must look back at the original sources from which we derive our understanding of the aseret yemei teshuvah.
The discussion of these days between Rosh Hashanah and Yom Kippur begins with a Gemara in tractate Rosh Hashanah:
R. Kruspedai said in the name of R. Yohanan: Three books are opened [in heaven] on Rosh Hashanah, one for the thoroughly wicked, one for the thoroughly righteous, and one for the intermediate. The thoroughly righteous are immediately inscribed and sealed for life; the thoroughly wicked are immediately inscribed and sealed for death; the intermediate is suspended from Rosh Hashanah until Yom Kippur; if they merit, they are inscribed for life; if they do not merit, they are inscribed for death (Rosh Hashanah 16b).
Rambam paraphrases this passage in Hilkhot Teshuvah (3:3) with a seemingly minor change:
Just as a person’s merits and sins are weighed at the time of his death, so too, the sins of every inhabitant of the world together with his merits are weighed on the festival of Rosh Hashanah. If one is found righteous, his [verdict] is sealed for life. If one is found wicked, his [verdict] is sealed for death. An intermediate person’s verdict is suspended until Yom Kippur. If he repents, his [verdict] is sealed for life. If not, his [verdict] is sealed for death.
Penei Yehoshua (Rosh Hashanah 16b s.v. ve-hinei) takes issue with this Rambam. Rambam changed the Gemara’s language of “merit” (zakhah) to “repent” (asah teshuvah). Aside from the issue of departing from the text of the Gemara, Penei Yehoshua asserts that conceptually Rambam’s change makes no sense. “Intermediate people,” at least according to Rambam’s own definition (Hilkhot Teshuvah 3:1) refers to people whose merits and sins are exactly equal. Any additional merit should be sufficient to push a person from the intermediate category to the righteous category. Why then should repentance specifically be necessary to have that person’s verdict sealed for life?
Answering the textual question is simple. Rambam followed the language of the Talmud Yerushalmi (Rosh Hashanah 1:3), which says “repent” rather than “merit.” The conceptual question, however, still stands, and is now not just a question on Rambam, but on the Yerushalmi as well. Many commentaries have attempted to answer Penei Yehoshua’s question on Rambam. However, the Gemara in Yoma 86b provides a very straightforward answer:
Reish Lakish said: Great is repentance, for willful sins are turned into errors… But didn’t Reish Lakish say: Great is repentance, for willful sins are turned into merits…There is no difficulty, one refers to [repentance] out of love, and the other refers to [repentance] out of fear.
This Gemara highlights the unique power of repentance. It is not merely another merit. Unlike any other Mitzvah or good deed, its performance does not merely make one a better person today. Whether out of love or fear, it has the unique power to retroactively undo the misdeeds of our past in the eyes of God, to make us better people, not just today, but also yesterday. Penei Yehoshua (and the Bavli) seem to see Yom Kippur as a new day of judgment. If we are in the intermediate category on Rosh Hashanah, God throws out that judgement and reevaluates us based on which category we are in on Yom Kippur. Thus, any additional merits are sufficient to push us out of the intermediate category and get us in the righteous category by Yom Kippur. For Rambam, however, there is only one day of judgment: Rosh Hashanah. If we are in the intermediate category on Rosh Hashanah, God will check the record books again on Yom Kippur. However, the judgment from Rosh Hashanah is not thrown out. There is no new judgement taking place on Yom Kippur. The record book is the same. It will only make a difference if God looks back and finds that you were actually in the righteous category on Rosh Hashanah–and only repentance can change the past deeds evaluated on Rosh Hashanah and turn them into merits. Thus, additional merits during aseret yemei teshuvah are a good start on next year’s judgment, but only repentance, with its power to retroactively change the past, will have an impact on this year’s judgment.
This approach yields two very different focuses for the aseret yemei teshuvah. Penei Yehoshua has a forward-looking aseret yemei teshuvah, focused on building up as many merits as we can in order to be worthy on Yom Kippur. Rambam, on the other hand, has a backward-looking aseret yemei teshuvah, focused on introspection and repairing our mistakes from the previous year. The widespread practice of eating only pat yisra’el certainly does not fit into Rambam’s understanding. Even within Penei Yehoshua’s understanding, it is still not clear why the focus should be on this rather than any other Mitzvah. Additionally, it must be noted that while I have provided a textual source and conceptual explanation for Rambam’s position, I have thus far not provided any explanation for why Rambam would choose the text of the Yerushalmi over the text of the Bavli. Answering this question will help us better understand how pat yisra’el fits into the picture.
In order to understand why Rambam quoted the Yerushalmi’s version of this passage rather than the Bavli’s version, we must look at the Biblical verses that each Talmud quotes in support of the idea of God’s three books. The Yerushalmi quotes a verse from Psalms 69:29, “May they be erased from the book of life, and not be inscribed with the righteous.” The context of this psalm is King David pleading with God to rescue him from his suffering, to save him from those who persecute him. “Deliver me, O God, for the waters have reached my neck (verse 2).” “They give me gall for food, vinegar to quench my thirst (verse 22).” The experience King David describes is an individual experience of suffering and persecution with universal relevance. There is nothing uniquely Jewish in these verses.
The Bavli, however, quotes another verse in addition to the one quoted in the Yerushalmi: “Now, if You will forgive their sin [well and good]; but if not, erase me from the book which You have written (Exodus 32:32).” Unlike the verse in Psalms, this verse has an extremely Jewish context. Moses pleads with God to forgive the Jewish people after the sin of the golden calf. God responds to Moses’ plea by saying, “Go now, lead the people where I told you. See, My angel shall go before you. But on the day of my accounting, I will bring them to account for their sins (32:34).” What does this phrase, “the day of my accounting” refer to? Ibn Ezra (ad loc.) says it means that the Jewish people will be held accountable for their sins on the first day of each year. Rashbam (ad loc.) proposes that it means that God will judge the Jewish people from time to time, as individuals, but not as an entire nation together. They are both getting at the same idea. The first day of the year, Rosh Hashanah, is, according to the Mishnah (Rosh Hashanah 1:2), a day of judgment for every individual in the world. God assents to Moses’ request not to wipe out the Jewish people, but will send an angel before them instead of leading them directly. Ibn Ezra and Rashbam interpret this to mean that the Jewish people will lose any special relationship they had with God as a nation, and exist merely as individuals. The people’s response to this is clear. “When the people heard this harsh word, they went into mourning (33:4).” Ultimately, God agrees to renew the special relationship with the Jewish people, resulting in the second set of tablets (34:1) and the 13 attributes of mercy (34:6-7). This final reconciliation took place on the 10th of Tishrei—the date that would become Yom Kippur (see Rashi on Exodus 33:11 s.v. ve-shav). Unlike Rosh Hashanah, Yom Kippur is not a day of judgment for the whole world, but is intimately connected to the special relationship between God and the Jewish people.
This understanding of the verses can illuminate the difference in language between the Yerushalmi and the Bavli. The Yerushalmi is focused exclusively on the universal experience of judgment as individuals, which applies to both Jews and non-Jews. It therefore sees Rosh Hashanah as the only real day of judgment. At most, God will wait until Yom Kippur to seal the verdict, but the verdict is ultimately based on one’s worthiness or lack thereof on Rosh Hashanah. Thus, the only way to reverse the initial verdict is through the power of repentance to retroactively change the past. The Bavli, which is focused not only on the universal experience of judgment as individuals, but also on the special relationship between God and the Jewish people, adds a new dimension to Yom Kippur, a dimension that emerges from the attribute of mercy that characterizes God’s new relationship with the Jewish people. Even if we fail to repent, fail to make ourselves worthy on Rosh Hashanah, God gives us a second chance. If we can make ourselves worthy through more good deeds to get more merit by Yom Kippur, that will be sufficient to undo the judgment we would have deserved on Rosh Hashanah. Rambam, in the passage quoted above, was talking about the judgment of “every inhabitant of the world” on Rosh Hashanah. Since, in halakhah 3, he was talking about Jews and non-Jews alike, he confined himself to the Yerushalmi’s more narrow understanding that only repentance is capable of changing the judgment. This does not mean, though, that he rejects the Bavli’s idea with respect to the special relationship between God and the Jewish people. In fact, in the very next halakhah he writes, “The entire house of Israel has accustomed themselves to increase their charity and good deeds, and to be involved in Mitzvot from Rosh Hashanah until Yom Kippur more than the rest of the year.” Here, when talking specifically about the Jewish people, he presents an approach to the aseret yemei teshuvah that is in line with the Bavli, and not limited to the backward-looking focus on repentance.
With this foundation, we are now able to explain the significance of being strict on pat yisra’el during the aseret yemei teshuvah. The basic Halakhah, based on the ruling of Shulhan Arukh (Yoreh De’ah 112:5), is that one is permitted to eat the bread of a non-Jewish baker if it is of a better quality than what is available from the Jewish baker. Being strict on pat yisra’el makes the statement that we want to show support for the bakers and businesses within our community, even if the quality is not quite as good, and even if it costs a little more. This focus on supporting and strengthening our ties to the Jewish community affirms the unique opportunity we have been given in the aseret yemei teshuvah. As individuals, our only hope is repentance and retroactively changing the past. It is only by connecting ourselves to the Jewish community that we are able to take advantage of the opportunity to better ourselves in other ways, and have our judgment completely reevaluated come Yom Kippur.
 When I shared this idea with Rabbi Elimelech Goldberg, he shared with me that he heard a similar explanation of this Rambam from Rabbi Aharon Kotler. The index in the Frankel Mishneh Torah (see note 4) also cites Rabbi Aharon Kotler as addressing this question in Mishnat Rebbe Aharon: Derashot, vol. 2, p. 179. I have not been able to locate a copy of the book to see if he says the same thing. See, however, Rabbi Aryeh Pomeranchik, Emek Berakha, pp. 146-147, and Rabbi Chaim Shmulevitz, Sihot Musar, p. 439, who explain similarly. My thanks to Moshe Kurtz for bringing these last two sources to my attention.
 With this idea, we can answer another challenge that Penei Yehoshua presents against Rambam. Rambam’s language indicates that one who remains in the intermediate category on Yom Kippur would be judged for death, and only one who actively moves themselves into the righteous category would be judged for life. Penei Yehoshua (ibid.) cites a parallel discussion the Gemara has (also Rosh Hashanah 16b) about the judgment a person undergoes after death. In that discussion, the Gemara concludes, based on God’s attribute of “abundant kindness (Exodus 34:6),” that a person whose merits and demerits are exactly equal would receive a favorable judgment. Penei Yehoshua assumes that this idea ought to apply to the yearly judgment on Rosh Hashanah/Yom Kippur as well. Based on what I have said, we can understand that “abundant kindness” is one of the 13 attributes of mercy that characterize God’s special relationship with the Jewish people, and therefore Rambam did not mention it when discussing the judgment undergone by every inhabitant of the world.
 For more details, see https://www.ou.org/torah/halacha/practical-halacha/pas-akum-part-2-pas-palter/.