The striking thing about the instructions for the oil used to light the seven-branched lamp in God’s sanctuary is where the instructions occur. They do not occur in chapter 26 when we learn about the lamp. Nor do they occur later when we learn about the incense used in the tabernacle, or when the fragrant anointing oil is described. The instructions for the oil that powers the oil lamps is given to us after the instructions for the perimeter fence and before the instructions for the priestly clothing.
When we think about the order in which the furnishings of the tabernacle are given, we find a certain motion. For example: the first thing described is the Ark of the Covenant, after which we move to the table and then the lamp. Then we get the tent itself and move on from that to the bronze altar outside the tent. Anybody who knows about the furnishings of the tabernacle will realize we haven’t had the smaller incense altar yet. That is something that goes inside the tent, and yet it is not described when every other item within the tent is. Clearly there are associations being made. This is what we need to do with the oil. We need to associate it with what surrounds it fully to understand what it means.
Once we are in the outer perimeter, which is what comes after the bronze altar and before the oil, we are in the area in which most of the priestly work was done, but not all. The priestly work also included a daily trimming of the lamps. With that daily trimming, we will eventually learn, there also came the offering of incense. But before that we have to have a priesthood.
So here is the order of events:
The oil is a way of connecting that which is continually harvested and continually brought through the camp to God’s dwelling, with the inner dwelling. It represents the best of the olive crop, the bounty, and it has a high and holy function: to shed light on the table in God’s house all night long. “The pure oil signified the gifts and graces of the Spirit, which are communicated to all believers from Christ the good olive, of whose fulness we receive (Zec. 4:11, 12), and without which our light cannot shine before men.” -Matthew Henry
Bringing the oil to its place is something only the priesthood can do, and so it is associated with them. It is something that must be constantly renewed, that comes from without and fuels the ongoing light and splendor of that place where prayers are offered up symbolically in incense by the high priest morning and evening when he trims the lamps. “This office God enjoins upon the priests, because they ought to be ministers of light when they are interpreting the Law, which David calls ‘the lamp of our feet, and the light of our paths.’” -John Calvin