The Messenger of Allah ﷺ said, "May Allah destroy the Jews. Fats were forbidden to them, yet they sold them and consumed the proceeds."
أن رسول الله ﷺ قال: قاتل الله يهودا، حرمت عليهم الشحوم، فباعوها، وأكلوا أثمانها.
Bukhari related it in "Sales" (2224), and Muslim in "Sharecropping" (1583), through Yunus (that is, Ibn Yazid Ayli), from Ibn Shihab, I heard Saeed bin Musayab, from Abu Hurairah, and he mentioned it. That is, the fat of a dead animal is not to be melted down, nor is it to be sold.