The church is lighted by lights after the pattern of the Tabernacle and the Sanctuary. They were full of lights and their lamps were never put out. The Lord commanded that the lamps be lighted by pure olive oil under the supervision of Aaron and his children as an everlasting statute. The Lord says: "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" (Ex.27: 20,21).
This is a Divine command, given by God who said on the first day of creation: “ ‘Let there be light’; and there was light. And God saw the light, that it was good" (Gen.1: 3,4).