30:17-21 A large vessel of brass, holding water, was to be set near the door of the tabernacle. Aaron and his sons must wash their hands and feet at this laver, every time they went in to minister. This was to teach them purity in all their services, and to dread the pollution of sin. They must not only wash and be made clean, when first made priests, but must wash and be kept clean, whenever they went to minister. It teaches us daily to attend upon God, daily to renew our repentance for sin, and our looking to the blood of Christ for remission; for in many things we daily offend.

18-21. Thou shalt … make a laver of brass—Though not actually forming a component part of the furniture of the tabernacle, this vase was closely connected with it; and though from standing at the entrance it would be a familiar object, it possessed great interest and importance from the baptismal purposes to which it was applied. No data are given by which its form and size can be ascertained; but it was probably a miniature pattern of Solomon's—a circular basin.

his foot—supposed not to be the pedestal on which it rested, but a trough or shallow receptacle below, into which the water, let out from a cock or spout, flowed; for the way in which all Eastern people wash their hands or feet is by pouring upon them the water which falls into a basin. This laver was provided for the priests alone. But in the Christian dispensation, all believers are priests, and hence the apostle exhorts them how to draw near to God (Joh 13:10; Heb 10:22).