Exodus 27:20 - Joseph Benson’s Commentary on the Old and New Testaments

Pure oil-olive beaten Not squeezed out by a press or mill, such being full of sediment; but which run freely from the olives when bruised or beaten with a pestle. To cause the lamp to burn always Josephus, who was himself a priest, says, they burned the lamps day and night, three of them being kept burning all day, and the rest being lighted in the evening. And indeed to keep them burning by day as well as night, was no more than what was necessary, for otherwise the priest must have ministered in the dark at the altar of incense; there being no windows in the holy place. Now the pure oil signifies the gifts and graces of the Spirit, which are communicated to all believers from Christ the good olive, “of whose fulness we receive,” Zechariah 4:11-12. The priests were to light the lamps, and to tend them; to cause the lamp to burn always, night and day. Thus it is the work of ministers to preach and expound the Scriptures, which are as a lamp to enlighten, the church. This is to be a statute for ever, that the lamps of the word be lighted as duly as the incense of prayer and praise is offered.