Let’s follow the progression of the past few mitzvos:
• Mitzvah #173: The metzora is sprinkled with the cedar, hyssop and other things, after which he is shaved all over.
• Mitzvah #174: A week later, the metzora is shaved again.
• Mitzvah #175: He must also immerse in a mikvah (as must all who seek ritual purification).
• Mitzvah #176 (this mitzvah): The next day (which is eight days after Mitzvah #173), the metzora brings a sacrifice to the Temple.
The offering of the metzora consists of two male and one female sheep, along with flour and oil. One male sheep is offered as a korban asham (guilt offering), blood from which is placed on the right ear, thumb and big toe of the metzora. The kohein sprinkles the metzora with some oil and rubs some over the blood on the ear, thumb and toe. (The rest of the oil goes on the metzora’s head.) After the kohein offers a korban chatas (sin offering), korban olah (burnt offering) and korban mincha (flour offering), the metzora is considered purified. If the three animals were beyond a metzora’s means, he was permitted to bring one sheep for his asham and two birds, either pigeons or doves, for his chatas and his olah.
The metzora is what’s called “mechusar kaparah” – “lacking atonement.” That means that even though he went through his purification process, including attending the mikvah and waiting until the sun set, he still may not eat holy things until after his sacrifice has been brought. Other examples of mechusarei kaparah are the woman who gave birth (Mitzvah #168) and the zav and the zavah, whom we’ll meet later in this parsha.
The reason for this mitzvah is to humble the metzora, all of whose problems were brought about by his former brazenness. This process is meant to accentuate the more noble qualities of a person so that he will not be tempted in the ways that led to his becoming a metzora in the first place.
This mitzvah applied to both men and women in Temple times. It is detailed in the Mishna in the fourteenth chapter of tractate Negaim; it is also discussed in the Talmudic tractates of Kerisos (8b) and Nazir (40a). This mitzvah is codified in the Mishneh Torah in the fourth chapter of Hilchos Mechusarei Kaparah and it is #77 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos.