Leviticus 24:2-4

2“Command the people of Israel to bring you pure oil of pressed olives for the light, to keep the lamps burning continually.

3This is the lampstand that stands in the Tabernacle, in front of the inner curtain that shields the Ark of the Covenant. Aaron must keep the lamps burning in the Lord’s presence all night. This is a permanent law for you, and it must be observed from generation to generation.

4Aaron and the priests must tend the lamps on the pure gold lampstand continually in the Lord’s presence.