286. 99 44/100% Pure: The obligation to offer only unblemished animals

Not only is it a violation of a negative mitzvah to offer a blemished sacrifice, it fulfills a positive mitzvah to offer an unblemished one.

The reason for this is what we said in the previous mitzvah: a sacrifice is meant to be of the finest kind, reflecting its importance. If people were to slack off and offer imperfect animals as sacrifices, it would denigrate the process, leading to a cycle of not taking the Temple service seriously and bringing inferior animals. By bringing perfect animals, we reiterate the importance of the service and hopefully set in motion a cycle of reverence and awe for God.

This mitzvah applies in Temple times. It is discussed in the Talmud in tractate Bechoros on pages 33b and 39a, and hither and yon in tractate Menachos (see, for example, page 56b). It is codified in the Mishneh Torah in the first chapter of Hilchos Issurei Mizbe’ach. This mitzvah is #61 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos.