Exodus 27:20-21

WEB_Strongs(i)
  20 H6680 "You shall command H1121 the children H3478 of Israel, H3947 that they bring H2134 to you pure H2132 olive H8081 oil H3795 beaten H3974 for the light, H5216 to cause a lamp H5927 to burn H8548 continually.
  21 H168 In the Tent H4150 of Meeting, H2351 outside H6532 the veil H5715 which is before the testimony, H175 Aaron H1121 and his sons H6186 shall keep it in order H6153 from evening H1242 to morning H6440 before H3068 Yahweh: H2708 it shall be a statute H5769 forever H1755 throughout their generations H1121 on the behalf of the children H3478 of Israel.