Then shalt thou take the anointing oil - It appears, from Isaiah 61:1, that anointing with oil, in consecrating a person to any important office, whether civil or religious, was considered as an emblem of the communication of the gifts and graces of the Holy Spirit. This ceremony was used on three occasions, viz., the installation of prophets, priests, and kings, into their respective offices. But why should such an anointing be deemed necessary? Because the common sense of men taught them that all good, whether spiritual or secular, must come from God, its origin and cause. Hence it was taken for granted,
Hence kings were inaugurated by anointing with oil. Two of these officers only exist in all civilized nations, the sacerdotal and regal; and in some countries the priest and king are still consecrated by anointing. In the Hebrew language משח mashach signifies to anoint, and משיח mashiach, the anointed person. But as no man was ever dignified by holding the three offices, so no person ever had the title mashiach, the anointed one, but Jesus the Christ. He alone is King of kings and Lord of lords: the king who governs the universe, and rules in the hearts of his followers; the prophet, to instruct men in the way wherein they should go; and the great high priest, to make atonement for their sins. Hence he is called the Messias, a corruption of the word המשיח hammashiach, The anointed One, in Hebrew; which gave birth to ὁ Χριστος, ho Christos, which has precisely the same signification in Greek. Of him, Melchizedek, Abraham, Aaron, David, and others were illustrious types. But none of these had the title of The Messiah, or The Anointed of God. This does, and ever will, belong exclusively to Jesus the Christ.
The consecration of the priests. See the notes to Exodus 29:4
Door of the tabernacle - Entrance of the tent. See Leviticus 8:3.
The “waving” was the more solemn process of the two: it was a movement several times repeated, while “heaving” was simply a “lifting up” once.
A stranger - One of another family, i. e. in this case, one not of the family of Aaron.