Musnad Ahmad 1153:1049

Waki’ narrated to us, he said: Abu ‘Aqil narrated to me, from Bahiyyah, from ‘Aishah, she said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "You must use the black seed, for in it is a cure for every disease except the *sam*," meaning: death. And the black seed is *ash-shuniz* (nigella sativa).