Exodus 30:18
Thou shalt also make a laver of brass, and his foot also of brass, to wash withal: and thou shalt put it between the tabernacle of the congregation and the altar, and thou shalt put water therein. Thou shalt also make a laver of brass, and his foot also of brass, to wash withal: and thou shalt put it between the tabernacle of the congregation and the altar, and thou shalt put water therein.
The command was for a laver of brass with a foot also of brass, filled with water, set between the altar of burnt offering and the tabernacle of the congregation, standing in the court beside the door and entrance of the sanctuary. Moses, Aaron, and Aaron's sons, the priests, washed their hands and their feet in its water, in sight of the congregation, before entering the tent and holy place or approaching the Lord at the sanctuary or altar to minister in the priest's office. In one account this washing came before putting on their pure linen garments distinctly specified for their sacred work.
The priests also left their shoes in the court, lest particles of dust desecrate the sanctuary hallowed by the glory of God. All who officiated were required to make this special preparation of washing to remove all impurity before entering where the glory of God was revealed. This was required because God is so high and holy that to minister without complying with these conditions would bring death.
The washing teaches that every particle of dust and all impurity, uncleanness, defilement, and everything like impurity must be put away from those who approach nigh to God and come into His holy presence. It shows that God is pure and holy, His service and work are sacred, everything connected with the work of God must be holy and free from uncleanness, and cleanliness and order with nothing slack and untidy are closely connected with acceptable and pure, holy worship. Done openly before the congregation, the washing was to make a right impression upon the people, impressing them with an exalted idea of God and His requirements and leading them to reverence Him and regard Him and His requirements with reverence. If those in sacred office fail to manifest care and reverence for God in apparel and deportment, the people will lose awe and reverence for God and His sacred service.
For ministers of sacred things this requires being pure and holy and clean and orderly in body, actions, dress, and apparel, with taste, order, neatness, and cleanliness. They are rightly to represent the principles of truth in their own lives and example and to bring the people up upon a high level, and not by untidiness and carelessness to bring the sacred down upon a level with common things. In this way every item will recommend the holy religion, and even dress itself will be a sermon to unbelievers.