John Gill Commentary Ezekiel 43:18

"And he said unto me, Son of man, thus saith the Lord Jehovah: These are the ordinances of the altar in the day when they shall make it, to offer burnt-offerings thereon, and to sprinkle blood thereon." — Ezekiel 43:18 (ASV)

And he said to me, son of man, thus says the Lord God This is the voice of the Lord continued, speaking out of the house to the prophet; see (Ezekiel 43:6) :

these are the ordinances of the altar : not what go before, concerning the measures of it, but what follow, concerning the sacrifices to be offered on it:

in the day when they shall make it, to offer burnt offerings on it, and sprinkle blood on it ; this plainly shows that this altar is the altar of burnt offerings; such were to be offered on it, and the blood of them to be sprinkled on it, as follows; that is, upon the horns, corners, and border of it, (Ezekiel 43:20) .