He Israelites were required to bring pure oil made of pressed olives to the tabernacle. The oils were needed to keep the lamps burning because it was never allowed to go out.

When you follow the principles of the oil, your light will shine forth in this dark world. Jesus is the light of the world, and He will also illuminate our path.

And you shall command the children of Israel that they bring you pure oil of pressed olives for the light, to cause the lamp to burn continually.  In the tabernacle of meeting, outside the veil which is before the Testimony, Aaron, and his sons shall tend it from evening until morning before the Lord. It shall be a statute forever to their generations on behalf of the children of Israel. (Exodus 27:20-21)