The same directions are in Exodus 40;
30 And he set the laver between the tent of the congregation and the altar, and put water there, to wash [withal].
31 And Moses and Aaron and his sons washed their hands and their feet thereat
The laver of water denotes laws of the Most High which are spirit that other places in scripture depict as a cleansing agent or simply as water, or a light.
The washing signified cleansing a soul before God, but to give you a broader picture of what the matter was here;
Even to the priests there was no access to features that are golden inside the tent, as well as the bronze altar on the outside without having ‘washed’ first with that water in the laver, because placement of all items of that structure signified generation gaps, while the features and elements symbolised servants of God themselves.
So the laver signified a servant of God at a point in time, Messiah, the word of God.
Messiah started the age of the divine, which culminates in a confluence of saints of all ages even from of old. This age starts at the coming of Messiah, in which is ‘the anointing the most Holy’ of Daniel 9:24.
All items labelled as ‘holy’ and ‘most holy’ to Aaron and sons where indoors in the Tent, and for the most part gold covered, and yet the altar of brass on the outside was also ‘most holy’.
These elements were distinguished as such because of a unique presence of the spirit of the Most High in the midst of the servants that they signify.
The Tabernacle denotes saints, the followers of Messiah, and not all saints, but the rulers, even then themselves in a different age from of the saints that the altar signifies, because spaces between the features of the tabernacle also signify time gaps.
The altar signifies saints that handle the very sacred things of the Most High wherever the symbol is used. The brass altar referred to the children of Israel, who were the only saints collectively associated with sacred duties towards God.
That’s why when blood of atonement was applied to the altar all Israel was atoned for, as they were the altar in whose ‘midst’ God was by His spirit.
Both male and female shall ye put out, without the camp shall ye put them; that they defile not their camps, in the midst whereof I dwell.
The nature of God’s dwelling in the midst of Israel would later change to that implied in Jeremiah 31, since God ‘dwells’ by His Spirit.
The water of cleansing in the laver are ‘laws by the power of His Spirit’ for cleansing a soul.
Being in between the bronze and the tent denotes these specific laws came after the age of the saints signified as the brass altar, yet some of the saints in that age of the ‘brass altar’ also walked in them, for example Moses who ‘shared’ the spirit that was on him with the 70 elders, as well as the prophets of old who were benefited in this special empowerment for righteousness, but which were not a full dispensation, only coming later than the times of the brass altar.
1 king 19:16...and Jehu the son of Nimshi you shall anoint king over Israel; and Elisha the son of Shaphat of Abel-meholah you shall anoint as prophet in your place.
See how the ‘anointing’ differs, for instance with kings and prophets, where one was for kingship another for prophecy.
That’s why anointing for kingship on people like David with that of prophecy could have them eat consecrated bread meant for only priests and get away with it because of the spirit on them that marked them out as good as ‘sons of Aaron,’ whereas the ‘anointing’ for kingship alone on kings like king Uzziah, a and a pious king, in offering incense which is a duty for priests alone, didn’t get away with it.
This is the kind of washing of the spirit of man meant here.
Aaron and his descendants signified the ‘Messiah and His ‘cleansed ones’ respectively, starting with the children of Jacob.
To go to the tent, the priests ‘became’ one with the servants signified by the Tent or the altar, a people spiritually purged in their ways, these ways symbolised as hands and feet.
That’s why Israel was enjoined up to shun gentile associations because gentile ways were ways of the ‘dead’ that would ‘defile’ them simply by touching, as also their cleansing came by symbolism of blood on the altar's walls.
That Aaron and sons would die if they would not wash signified an apostate state, or at the very least a hypocritical profession in which state any man found is considered ‘dead’ before God, which state was indicated by their physical death.
Exodus 40:31 And Moses and Aaron and his sons washed the feet and the hands,
Aaron’s name connotes a light bearer, which light opens eyes of the peoples in darkness, and Moses’ name indicates rescue from the waters of one in danger of perishing, these names have connotations of the Most High getting sons from all nations and tongues, these peoples signified as waters, Rev 17:15.
All are to walk in conformity to a specific forms of laws of YAH, in that their ways would have to be patterned after the requirements of these laws of YAH.
That’s the washing of the feet and the hands before entering the tent or touching the brazen altar.