Albert Barnes Commentary Jeremiah 16:18

"And first I will recompense their iniquity and their sin double, because they have polluted my land with the carcasses of their detestable things, and have filled mine inheritance with their abominations." — Jeremiah 16:18 (ASV)

First - Before the return from exile.

I will recompense their iniquity ... double - The ordinary rule of the Law (Isaiah 40:2 note). Sin is twofold; there is the leaving of God’s will undone, and the actual wrongdoing. And every punishment is twofold: first, there is the loss of the blessing which would have followed upon obedience, and secondly, the presence of actual misery.

Because they have defiled ... - Rather, because they have profaned My land with the carcases of their detestable things (their lifeless and hateful idols, the very touch of which pollutes like that of a corpse, Numbers 19:11); and have filled My inheritance with their abominations.