Leviticus 24:2-4

2‘Tell Israel's people that they must bring to you the best oil. This will cause the light to burn all the time.

3Aaron must put more oil in the lamp from evening to morning in front of the Lord. The lamp is outside the curtain. That curtain is in the Holy Place. The light must never go out. This rule is for now and for all time to come.

4The lamps on the gold lampstand must burn always in front of the Lord.