Exodus 30:8-10

Amplified Bible

⁸ When Aaron sets up the lamps at twilight, he shall burn incense, a perpetual incense before the Lord throughout your generations. ⁹ You shall not offer any strange incense on this altar, or burnt offering or meal offering; you shall not pour out a drink offering on it. ¹⁰ Once a year Aaron shall make atonement [for sin] on its horns. He shall make atonement on it with the blood of the sin offering of atonement once a year throughout your generations. It is most holy to the Lord.”