Exodus 30:8

And when Aaron lighteth the lamps at even, he shall burn incense upon it, a perpetual incense before the LORD throughout your generations.

Aaron ... shall burn incense - seemingly limiting the privilege of officiating at the altar of incense to the high priest alone; and there is no doubt that he and his successors exclusively attended this altar on the great religious festivals. But "Aaron" is frequently used for the whole priestly order; and in later times any of the priests might have officiated at this altar in rotation (Luke 1:9).

Every morning ... at even - in every period of the national history this daily worship was scrupulously observed.