Most of what I have to say on this topic comes from R. Yaakov Charlop’s article in Techumin 25 on the topic, though I’ve added a few sources here and there. The shiur is available here.
First, it is clear that the categories of Kiddush Hashem and Chillul Hashem are very important. As the Gemara highlights at the end of Yoma, causing a Chillul Hashem is considered a sin in a class of its own, which either requires death to achieve atonement (Rambam), or death cannot offer atonement and the sinner loses his portion in the world to come (R. Yonah). R. Yonah explains that as all creatures are created to bring glory to God, desecrating his name undermines a person’s reason for existence. God also does not delay punishment for this sin (Kiddushin 40). Chillul Hashem and Kiddush Hashem can be brought about through the performance/lack of performance of mitzvoth, or from being careful/derelict in acting in an ethical/societally acceptable manner. Highlighting the latter issue, the Gemara emphasizes that a Talmid Chacham should not push off paying his loans when it is not acceptable, walk without Torah, etc. The Gemara also suggests that Kiddush Hashem is a function of the mitzvah to love God. While the paradigmatic cases of Chillul Hashem and Kiddush Hashem relate to martyrdom, the colloquial notions are also critical (see my article in Beit Yitzchak 41 and R. Aharon Solovetichik’s article in Kavod HaRav on the connection between these two types of Kiddush Hashem.)
The main focus of the shiur was the role of Chillul Hashem as a factor in psak. I chose a few examples that highlighted the issues.
- Chillul Hashem Creating Issurim or Chumrot:
- Masechet Kutim and Sefer Chasidim have discussions about forbidding buying or eating food that is perfectly kosher but non-Jews look askance at. This is a practical concern that generates a new issur based on concerns of Chillul Hashem. [Cherem D’Rabbenu Gershom is related to this as well.]
i. In this case, there seems to be no Torah values reflected by the issur created – it is purely pragmatic.
- Sometimes this is more fundamental. For example, the Shoel UMeshiv argues it would be embarrassing to Torah if it did not recognize copyright law which is recognized by the whole world. This seems to reflect a value that the Torah legitimately should incorporate into law. Thus, even if the issur is hard to pin down, it is assur to violate copyrights.
- In the Yerushalmi, Shimon ben Shatach returns a jewel to a non-Jew, although aveidat goy is mutar, and argues that he is not a barbarian and would like the non-Jew to bless the God of the Jews. This seems to be another case where the concern for Chillul Hashem is actually a reflection that to not hold oneself to the standard dictated by this ethic would be fundamentally problematic. [This is difficult in the Bavli and the subsequent psak of Rambam.]
- As a factor for leniency:
- The Rambam eliminated private shemonah esre (and only had a public one) because the talking was a chillul Hashem. The Radbaz agreed in theory, but argued that in his world the claim was no longer true.
- The Ben Ish Chai was mekal to allow giving coffee to non-Jewish guests on a Moed, even if it would force the Jews to cook more, and called this a tzorech – you have to be a good host. Otherwise it would be a chillul Hashem.
- In a striking teshuvah, R. Ovadiah is mekal and allows the Karaites to marry Rabbinic Jews because it would be a Chillul Hashem to reject people who had given up their lives as Jews both in the past and as soldiers in the State of Israel. He accepts this argument from the Besamim Rosh, even though he believes it to be a forgery- arguing that the logic is compelling. The language is extremely striking, including an argument from the Besamim Rosh that if it was not mutar m’ikkar hadin, it would be worth uprooting the Torah to reach this conclusion!
- A Double Edged Sword
- Sometimes it is not clear where the argument goes. There was apparently a machloket in Italy whether allowing people to shave on Chol HaMoed would prevent the Chillul Hashem in the eyes of the world of looking disheveled on Yom Tov (because of a gzeriah meant to force people to look good on Yom Tov), or would cause Chillul Hashem because it would show the world that we change our laws.
- As a reason to punish
- The Gemara says the Bnei Shaul were punished to appease the Givonim, as Shaul’s mistreatment of them had caused a Chillul Hashem.
- R. Kook develops this as a general idea.
- Jews or non-Jews:
- There is a machloket, but limaskana it seems like a Chillul Hashem could be in front of either. See the summary I included in the sources.