If somebody declares that he’s going to bring wood for the Mizbeach (altar), he uses the word etzim (wood), but he doesn’t specify how much wood he’s going to bring. He has to bring at least two wooden logs. The word etzim is plural, so the minimum for the plural is two, and he therefore has to bring two logs. If he says, “I’m donating etz to the Mizbeach,” he can only bring one. Etz is singular, so he’s allowed to bring only one.
If someone declares that he’s going to bring levonah (frankincense), and he doesn’t say how much, he has to bring at least a kometz of levonah, which is the measurement between the three middle fingers of a person’s hands when they’re placed towards his palm. Chamishah kematzim hen: there are five laws that involve the measure of a kometz. Ha’omer harei alai levonah: somebody who says, “I accept to bring levonah to the Beit HaMikdash (Temple).” Lo yifchot mi’kometz: you should not bring less than a kometz, like we stated above. Hamitnadev mincha (meal offering), yavi imah kometz levonah: somebody who donates a mincha has to bring with it a kometz of levonah as well. Levonah is brought with all of the menachot, and it’s burned on the ... and it’s burned together with the kometz of flour of the mincha. Hama’aleh kometz bachutz chayav: somebody who offers a kometz of a mincha outside the Beit HaMikdash is karet (excision) for doing so. Anyone who offers any korban (offering) outside the Beit HaMikdash once it was built is liable for karet for that action. Ushnei bazichin (spoonfuls) te’unin shnei kematzim: there are two spoonfuls of levonah that are placed on the shulchan (table) with the kometz of the Beit HaMikdash, and with the Lechem HaPanim (showbread) they require two kematzim as well. The levonah that’s placed with the Lechem HaPanim: each one of them has to be the measurement of a kemitzah (handful).