Matthew Henry on Exodus 27:20-21

The pure oil signified the gifts and graces of the Spirit, which all believers receive from Christ, the good Olive, and without which our light cannot shine before men. The priests were to light the lamps, and tend them. It is the work of ministers, by preaching and expounding the Scriptures, which are as a lamp, to enlighten the church, God's tabernacle upon earth. Blessed be God, this light is not now confined to the Jewish tabernacle, but is a light to lighten the gentiles, and for salvation unto the ends of the earth.