Exodus 29:4 - Joseph Benson’s Commentary on the Old and New Testaments

Unto the door of the tabernacle God was pleased to dwell in the tabernacle, the people attending in the courts, so that the door between the court and the tabernacle was the fittest place for them to be consecrated in who were to mediate between God and man, to stand between both, and, as it were, lay their hands on both. Thou shalt wash them with water To signify that they must be clean who bear the vessels of the Lord, Psalms 50:16; Isaiah 52:11. Ablution was an ancient rite in all acts of worship, as a proper emblem of sanctifying grace, and internal purity, without which external oblations and services are of little signification before God. As this was the first thing that was done for hallowing the priests, (Leviticus 8.,) it is probable their whole bodies were now washed, in token of the necessity of their being washed from all their sins by pardon and regeneration, and thoroughly renewed in heart and life, that they might begin their services aright: but afterward they were appointed to wash only their hands and their feet before they entered the tabernacle, (Exodus 30:19, &c.,) to remind them of those daily imperfections from which even such as are regenerated and created anew have need to be cleansed by a daily application of pardoning mercy, through the blood of atonement. Thus the Lord Jesus, “He that is washed needeth not save to wash his feet, but is clean every whit.”