Sefer HaChinuch ספר החינוך

The commandment of wearing the priestly clothes: That the priests were commanded to wear special clothes for aggrandizement and glory — and then they may serve in the Temple — as it is stated (Exodus 28:4), “and they shall make priestly clothes for Aharon your brother and his sons.”

From the roots of the commandment is the principle established for us, that a person is impacted according to his actions and pursuant to his thoughts and intentions. And the agent that atones must attach all of his thoughts and intentions to the [Divine] service. Therefore, it is fit that he wears special clothes for it; as when he stares at any place of his body, he will immediately remember and be aroused in his heart as to in front of Whom he is serving. And this is like the tefillin that all have been commanded to place on a part of the body, that it be to remember proper thought. And even though the priest also wears tefillin, due to the greatness of his matter, he needs this too.

And from this reason we can [explain that] which is said (Pesachim 65b) that the length of the robe is obligated to be upon all of his body, from above to the heel below; the length of its sleeve be to the palm of his hand (Yoma 72b); the length of the turban be sixteen ells (Mishneh Torah, Laws of Vessels of the Sanctuary and Those Who Serve Therein 9:19) and wrap the whole head, so that he see it any time he raises his eyes; and the length of the sash that he wraps on his loins be thirty-two ells and he wraps and rewraps it on his body, one layer over another, and it comes out that he feels it with his forearms all the time, as due to its thickness from all the wrappings, his forearms touch it regardless. And all of this is a proof to that which we have said, for the one who concedes the truth. Besides [this reason], there is glory to the Temple and to the [Divine] service in the matter that the servant wears special clothes for the service. And we have already written (Sefer HaChinukh 95) that with the aggrandizement of the Temple and its fear, the hearts of sinners will be softened and they will repent to God.

And the laws of the commandment are, for example, the elucidation of the clothes, which are three types, one type of regular priestly clothes and two types of high priestly clothes — the gold clothes and the white clothes. And [the garments] of a regular priest are four, and their names are like this: robe (ketonet), trousers (mikhnasayim), turban (migbaat) and sash (avnet). The robe is like a wide Yishmaelite cloak. And the form of the trousers is well-known in every place, but theirs were big, from the loins to the thighs — meaning to say until the [part of the] thighs which [in the vernacular] is called the genoi (knee). However the turban is a garment that is placed upon the head, made like a hat. The sash is a type of belt with which he girds himself, except that they wrap it around themselves many [times], which we do not do with a belt. And these four linen garments were white and their string was six-stranded (Yoma 71b). And only the sash was embroidered with wool (Yoma 12b). And the regular priest would always serve in them, and it is permissible for him to wear them during the day, whether during the time of the service or not during the time of the service — as it is permitted to derive benefit from them. [This is] except for the sash, since it is shaatnez (an otherwise forbidden mixture of fibers). And therefore it is forbidden not during the time of the service.

And [the garments] of the high priest are eight, and their names are like this: robe (ketonet), trousers (mikhnasayim) and sash (avnet) — like the names of the three of the regular priest — and mitsnefet (miter) was for the high priest instead of the turban of the regular priest. As this and that were [both] placed on the head, except that the miter is made like a long type of cloth that women coil around their heads — and the high priest would coil himself with it — but the turban is made like a type of hat (that does not require coiling). Behold, [these] four of the high priest, which were only of linen, were white, six-stranded and embroidered, but their embroidery was not similar to the embroidery of the regular priest’s sash. And he also had four others of gold and their names were breastplate (choshen), apron (ephod), coat (me’il) [and] headband (tsits). And he would do the external service with all of the eight, but inside — which is past the partition — he would never serve with anything but the [linen] clothes. And after he served with them for one Yom Kippur, he does not repeat to ever serve with them (Yoma 24a), as it is stated (Leviticus 16:3), “and he leaves them there.” And anytime a priest — whether a regular or a high [priest] — serves with less than the clothes that are designated for that service, or more than them, his service is disqualified. And he is also liable for the death penalty by the hand of the Heavens, as our rabbis, may their memory be blessed, learned (Sanhedrin 83b, Zevachim 17b-18a) from “And you shall gird them with a sash [...] and they would have priesthood” (Exodus 29:9) — at the time when their clothes are upon them, their priesthood is upon them; when their clothes are not upon them, their priesthood is not upon them. And they are [hence] considered like a stranger (a non-priest) who transgresses, which is [punishable] by death. [These] and the rest of its details are elucidated in the second chapter of Zevachim and in places in Yoma and Sukkah. (See Mishneh Torah, Laws of Vessels of the Sanctuary and Those Who Serve Therein 10.)

And this commandment is practiced at the time of the Temple by males of the priesthood. And one who transgresses it and served lacking [priestly] clothes or [with too many] is liable for the death penalty by the hand of the Heavens, as we have written.