Exodus 27:21
In the tabernacle of the congregation without the veil, which is before the testimony, Aaron and his sons shall order it from evening to morning before the LORD: it shall be a statute for ever to their generations on the behalf of the children of Israel.
Torrey's Topical Textbook—AKJV

Exodus 30:8
And when Aaron lights the lamps at even, he shall burn incense on it, a perpetual incense before the LORD throughout your generations.
Torrey's Topical Textbook—AKJV