Thus shall Aaron come into the holy place: with a young bullock for a sin offering, and a ram for a burnt offering. He shall put on the holy linen coat, and he shall have the linen breeches upon his flesh, and shall be girded with a linen girdle, and with the linen mitre shall he be attired: these are holy garments; therefore shall he wash his flesh in water, and so put them on.
Leviticus 16:3-4 KJV commentary https://bible.com/bible/1/lev.16.3-4.KJV
Coming before God was definitely uncommon and required such copious preparation.
It hammered home the point, that his presence is rare and is to be respected.
It’s same with the laws of cleanliness. To avoid spreading of disease and the tedious washing of clothes just because you touched someone or something.
Such requirements ensured the presence of God and his laws was constantly in their mind
Thus shall Aaron come into the holy place: with a young bullock for a sin offering, and a ram for a burnt offering. He shall put on the holy linen coat, and he shall have the linen breeches upon his flesh, and shall be girded with a linen girdle, and with the linen mitre shall he be attired: these are holy garments; therefore shall he wash his flesh in water, and so put them on.
Leviticus 16:3-4 KJV https://bible.com/bible/1/lev.16.3-4.KJV
He shall put on the holy linen coat, and he shall have the linen breeches upon his flesh, and shall be girded with a linen girdle, and with the linen mitre shall he be attired: these are holy garments; therefore shall he wash his flesh in water, and so put them on.
Leviticus 16:4 KJV https://bible.com/bible/1/lev.16.4.KJV
Why do I have the feeling that angels and spirit being have a mechanism that prevents dirt from getting to them.
And the shadow of that is the cleansing of the flesh with water . That is the purpose of ceremonial cleansings.
Same also spirits have their outer garments as part of them, it was part of their glorios bodies, so in like manner Aaron was to be well covered in his flesh :
From the breaches to the holy crown