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.

11-16. When thou takest the sum of the children of Israel, &c.—Moses did so twice, and doubtless observed the law here prescribed. The tax was not levied from women, minors, old men (Nu 1:42, 45), and the Levites (Nu 1:47), they being not numbered. Assuming the shekel of the sanctuary to be about half an ounce troy, though nothing certain is known about it, the sum payable by each individual was two and four pence. This was not a voluntary contribution, but a ransom for the soul or lives of the people. It was required from all classes alike, and a refusal to pay implied a wilful exclusion from the privileges of the sanctuary, as well as exposure to divine judgments. It was probably the same impost that was exacted from our Lord (Mt 17:24-27), and it was usually devoted to repairs and other purposes connected with the services of the sanctuary.