God gave Moses the design for the Levitical priestly garments.
As GOD continued revealing His will to Moses upon Mount Sinai, He prescribed specific clothing for the Levitical priests to wear.
1 “Now take Aaron your brother, and his sons with him, from among the children of Israel, that Aaron, Nadab, Abihu, Eleazar, and Ithamar may minister to Me. 2 Then you shall make a holy garment for Aaron your brother, for honor and glory. 3 So you shall speak to all who are wise in understanding, whom I filled with the spirit of wisdom and perception, so they may make Aaron's holy vestments for the sanctuary, in which he shall minister to Me as priest. 4 These are the garments they shall make: a breastplate, an ephod, a full-length robe, a skillfully woven tunic with a fringe, a turban, and a sash. So they shall make holy garments for Aaron your brother and his sons, so they may minister to Me as priests. 5 They shall take the gold, blue, purple, and scarlet fabric and fine linen, 6 and they shall make the ephod of fine spun linen, the woven work of a designer. 7 The two parts of the ephod shall be joined together, attached at their two hems. 8 The woven joining of the ephod, which is on it, shall be of the same workmanship, made of pure gold, and blue, purple, and scarlet fabric, and fine woven linen. 9 Then you shall take two stones, emeralds, and engrave on them the names of the sons of Israel: 10 six of their names on one stone, and six names on the other stone, in the order of their birth. 11 With the work of the stone-engraver's art, the engraving of a seal, you shall engrave the two stones with the names of the sons of Israel. 12 You shall put the two stones on the shoulders of the ephod as memorial stones for the sons of Israel. So Aaron shall bear their names before the Lord on his two shoulders as a memorial. 13 You shall also make bosses of gold, 14 and you shall make two fringes of pure gold intermixed with flowers, a braided work, and fasten the braided fringes to the bosses on the shoulder bands in front.
15 “You shall make the oracle of judgment. Artistically woven according to the style of the ephod you shall make it: of gold, blue, purple, and scarlet fabric and fine spun linen you shall make it. 16 It shall be doubled into a square: a span shall be its length, and a span its width. 17 Interwoven into this texture shall be a setting for four rows of stones. There shall be a row for a sardius, a topaz, and an emerald. This shall be the first row. 18 The second row shall be a carbuncle, a sapphire, and a jasper; 19 the third row, a jacinth, an agate, and an amethyst; 20 and the fourth row, a chrysolite, a beryl, and an onyx. They shall be set in gold settings, bound together with gold, according to their row. 21 The stones shall have the names of the sons of Israel, twelve according to their names, as the engravings of seals, each one with its own name; they shall be according to the twelve tribes. 22 You shall make chains for the oracle, a braided work of pure gold. 23 Aaron shall bear the names of the children of Israel upon the oracle of judgment on his breast, as a memorial before God for him as he goes into the sanctuary. 24 You shall put fringes upon the oracle of judgment, and wreaths on both sides of the oracle. You shall put the two bosses on both shoulders of the ephod in the front. 25 You shall put the revelation and the truth on the oracle of judgment, which will be on the breast of Aaron when he enters the holy place in the Lord's presence; and on his breast Aaron will discern the judgments for the children of Israel at all times.
26 “To go underneath the ephod, you shall make a full-length robe, entirely blue. 27 In the middle of it there shall be an opening for the head, the collar bordered in sheepskin, a woven piece. The hem shall be interwoven with the rest, to prevent ripping. 28 Beneath the border of the robe you shall make knobs as of a flowering pomegranate, constructed of blue, purple, and scarlet fabric and fine spun linen, all around the hem of the garment. 29 Hanging from each golden knob will be a flower-shaped bell all around the hem of the garment. 30 Its sound will be heard when Aaron is serving as a priest, entering and leaving the holy place before the Lord, that he not die. 31 You shall also make a plate of pure gold and, as the inscription of a seal, engrave on it: Holiness to the Lord. 32 You shall put it on a blue cord, and it shall be on the turban. It shall be on the front of the turban. 33 So it shall be on Aaron's forehead. Aaron shall take away the defilements of the holy things which the children of Israel might dedicate, of their every gift of holy things. It shall always be on Aaron's forehead to make them acceptable before the Lord.
34 “The appointments of the robes you shall make of linen. You shall make the turban of fine linen, and you shall make a sash of woven work. 35 For Aaron's sons you shall make robes and sashes for them, and turbans you shall make for them for honor and glory. 36 So you shall put them on Aaron your brother and on his sons with him. You shall anoint them, consecrate their hands, and sanctify them so they may minister to Me as priests. 37 You shall make for them trousers to cover their naked skin from loin to thigh. 38 Thus Aaron and his sons shall wear them when they come into the tabernacle of testimony or when they come near the altar of the holy place to minister as priests, so they not bring guilt upon themselves so as to die. It shall be an ordinance forever to him and his seed after him.
(Exodus 28:1-38 OSB)
The high priest, beginning with Aaron, was to wear a special:
- Breastplate (aka the oracle of judgment)
- Trousers (aka shorts/underwear)
The other priests were to wear special:
Priestly garments were critical. Without proper attire, GOD would strike the priest dead.