Sunan An-Nasai, Chapter: The Book of the Masjids

that Umm Habibah and Umm Salamah mentioned a church that they had seen in Ethiopia, in which there were images. The Messenger of Allah (saw) said: "Those people, if there was a righteous man among them, when he died they built a place of worship over his grave and made those images. They will be the most evil of creation before Allah on the Day of Resurrection." (Sahih)