You shall further instruct the Israelites to bring you clear oil of beaten olives for lighting, for kindling lamps regularly. Aaron and his sons shall set them up in the Tent of Meeting, outside the curtain which is over [the Ark of] the Pact, [to burn] from evening to morning before the LORD. It shall be a due from the Israelites for all time, throughout the ages.
Exodus 27:20-21