Charles Ellicott Commentary Ezekiel 6:13

"And ye shall know that I am Jehovah, when their slain men shall be among their idols round about their altars, upon every high hill, on all the tops of the mountains, and under every green tree, and under every thick oak, the places where they offered sweet savor to all their idols." — Ezekiel 6:13 (ASV)

Upon every high hill. —The various localities especially selected for idolatrous rites are enumerated one after another, to give more vividness and graphic character to the whole judgment. The words sweet savour are constantly applied to the commanded sacrifices to the Lord, and are here used ironically of the idol sacrifices.