Jami` at-Tirmidhi 637

Amr bin Shu'aib narrated from his father, from his grandfather, :that two women came to the Messenger of Allah, and they each had a bracelet of gold on their forearms. So he said to them: "Have you paid their Zakat?" They said, "No." The Messenger of Allah said to them: "Would you like for Allah to fashion then into two bracelets of Fire?" They said, "No." He said: "Then pay its Zakat