The Rambam's Twelfth Principle: The specific actions of a mitzvah are not themselves mitzvos

God said, “Build Me a sanctuary” (Exodus 25:8). He then told the Jews how to do this. You need an altar. You need a shulchan (table). You need a menorah. There’s a lot to do to fulfill this mitzvah. But each action isn’t a separate mitzvah. Rather, they are all part of fulfilling the mitzvah of building the Temple.

Similarly, it’s a mitzvah to offer a korban olah (burnt offering). Doing so requires that the animal be slaughtered, skinned, and cut up, its blood sprinkled in a particular manner, its fats burned and its meat offered with particular amounts of flour and wine, after which the Kohein who performed the offering receives the animal’s hide. All of these actions are part of fulfilling a single mitzvah: that of offering a korban olah. (Other types of sacrifices have their own details.)

The exception to this principle are things that must be done for all different types of sacrifices. Since they are not unique to the burnt offerings or sin offerings, they are not specifically part of those mitzvos. For example, an animal with a defect may not be used for any type of sacrifice. Therefore, the prohibition against using a blemished animal is its own mitzvah, not part of the law of burnt offerings. (Similarly, the prohibition against offering an animal under eight days old or the obligation to salt an offering are their own mitzvos and not actions associated with any particular type of sacrifice.)

Having demonstrated this distinction, the Rambam applies it to priestly and Levitical gifts. The hide of a burnt offering is part of the law of burnt offerings, but giving a kohein the first shearing is a mitzvah in and of itself. But some previous compilers of Taryag lists erred and counted each of the 24 priestly gifts as separate mitzvos when most of them are in fact part of larger mitzvos (like the hide of a burnt offering).

Along the same lines, those who counted all the waving, pouring, salting, burning, etc. of a flour offering were mistaken, as these are all actions of a single mitzvah. This is no different than the example of chalitzah, in which the widow of the deceased man removes the brother-in-law’s shoe, spits in his general direction, and recites a particular passage. Everyone recognizes that these are all actions of one mitzvah. It’s the same with sacrifices, building the Temple, and other mitzvos that require many things to be done.