A quick halacha (Jewish law) today: The Beit Yosef mentions the halacha that for birkat Kohanim (the priestly blessing), you need to have 10 gedolim (adults), 10 male gedolim, like any davar shebikdusha (matter of sanctity). The question is, can you count the Kohanim inside the minyan (quorum of ten), or do you need to have a minyan besides the Kohanim? They are blessing a congregation. Maybe you need to have 10 people receiving the beracha (blessing).
The Beit Yosef mentions the Gemara in Ketubot, Daf Chet (page eight), which says: Birkat Chatanim be'asara, veha-chatanim min ha-minyan (The blessing of grooms is with ten, and the grooms count toward the quorum). So you have birkat Kohanim, for example; you bless the Kohanim, and they're part of the minyan. So too, says the Beit Yosef, it's the same thing: we don't find that, for a davar shebikdusha, you need to have 10 besides the one who is officiating.
The Levush, very interestingly, says, Va'ani avarechem. It says that Va'ani avarechem also includes the Kohanim, which means the beracha is all-encompassing, including both. Really, there are two parts in the beracha: the one who is giving and the one who is receiving. But really, everybody is receiving, because Hashem says, Va'ani avarechem. Although we saw that the peshat (plain meaning) of the Rambam didn't work with that, because Va'ani avarechem was saying, I will bless the Yisrael, not the Kohanim. But anyway, that's the source for why we need 10 people for birkat Kohanim.
This case is very interesting. The Rashba is the one who mentioned the following: whenever you start a davar shebikdusha and somebody leaves, you continue the davar shebikdusha. For instance, if you start the Chazara (repetition of the Amidah) with 10 people, and one person has to leave in an emergency, you continue the Chazara till the end, including the Kedusha (sanctification). The question, Rabotai (my masters), is: do you make birkat Kohanim in this case? The she'elah (question) really is very simple. Is birkat Kohanim part of the Chazara, or is birkat Kohanim not part of the Chazara? It is just that, for technical reasons of Sherut in the Beit HaMikdash, to mirror what they used in the Beit HaMikdash, we do it at the time of the Avodah (Temple service), when we mention the Beit HaMikdash. But really, birkat Kohanim has nothing to do with the Chazara.
Now, we've seen a source in the Yerushalmi that tells us, Ein Birkat Kohanim ba-layla (There is no priestly blessing at night). Mashma, that there was never a problem with the problem of the Chazara, because there's no Chazara at night anyways. But the reason is not the Chazara. So we see that there's no problem with that. It seems that birkat Kohanim has nothing to do with the Chazara, and here again is the question: do you say birkat Kohanim when a person leaves in the middle, or not? Or are they two different mitzvot (commandments)? It's a big makhloket (disagreement) in the Aharonim (later authorities).
The Torah Chaim, Sofer and the Shevet Yehuda say that you continue; it's part of the Chazara. But most poskim (halachic decisors) disagree with this, and the Yerushalmi is Meforash (explicit). Really, it's a little surprising, because the Yerushalmi is clear on this: you continue the Chazara, but the Yerushalmi says that if you start the birkat Kohanim with ten, then you continue the birkat Kohanim. Mashma, you have to begin the birkat Kohanim with ten people, and it's Mashma that birkat Kohanim is not part of the Chazara, and that is halacha lemaaseh (practical halacha). This is a psak (ruling) of Rav Shmuel Wosner and Rav Ovadia Yosef, that if it could happen lemaaseh that somebody leaves in the middle of the Chazara and you have only nine people left, you complete the Chazara, but you do not do the birkat Kohanim.