Musannaf Ibn Abi Shayba 16:663

Abu Bakr narrated to us, he said: Yazid bin Harun narrated to us, he said: Hammad bin Salama narrated to us, from Abu al-Muhazzam, from Abu Hurayrah, that the Prophet, may Allah bless him and grant him peace, said to Fatimah or to Umm Salamah: "Your hem is a cubit."