Albert Barnes Commentary Jeremiah 44:21

"The incense that ye burned in the cities of Judah, and in the streets of Jerusalem, ye and your fathers, your kings and your princes, and the people of the land, did not Jehovah remember them, and came it not into his mind?" — Jeremiah 44:21 (ASV)

Them — The various acts of idolatry involved in burning incense to an image.