Charles Ellicott Commentary Leviticus 16:13

"and he shall put the incense upon the fire before Jehovah, that the cloud of the incense may cover the mercy-seat that is upon the testimony, that he die not:" — Leviticus 16:13 (ASV)

And he shall put the incense. —The high priest now threw the incense upon the coals in the censer, in the Holy of Holies. He stayed there until the whole place was filled with a cloud of smoke, taking special care that the mercy seat and the cherubim should be enveloped in the cloud.

Upon which, he left the Holy of Holies, walking backward, with his face to the Holy Place and his back to the Temple.

Upon his emerging from within the second veil and arriving in the Holy Place, he pronounced the following prayer:—“May it please You, O Lord my God, that if this year was intended to be one of drought, it may be one of rain. May he who rules over the house of Judah not die. May Your people not be in want, so that one should beg for bread from another or from strangers; and do not let the prayers of travelers come before You” [because they pray that no rain may fall].