Ezekiel 4:12-15

You will eat it as you would a barley cake and bake it over dried human excrement in their sight.” The Lord said, “This is how the Israelites will eat their bread — ceremonially unclean — among the nations where I will banish them.”  But I said, “Oh, Lord God, I have never been defiled. From my youth until now I have not eaten anything that died naturally or was mauled by wild beasts.  And impure meat has never entered my mouth.”  He replied to me, “Look, I will let you use cow dung instead of human excrement, and you can make your bread over that.”