Leviticus 24:2-4

2“Command the children of Israel to bring to you clear oil from beaten olives for the light [of the golden lampstand], to make a lamp burn continually.

3Outside the veil of the Testimony [between the Holy Place and the Most Holy Place] in the Tent of Meeting, Aaron shall always keep the lamps burning before the Lord from evening until morning; it shall be a permanent statute throughout your generations.

4He shall keep the lamps burning on the pure gold lampstand before the Lord continually.