Musnad Abu Ya'la al-Mawsili 155:78

Abu Khaythama narrated to us, Yahya bin Sa'id narrated to us, Muhammad bin 'Amr narrated to us, he said: Abu Salamah narrated to me, from Abu Hurayrah, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The black seed is a cure for every disease except the Sam." They said: "And what is the Sam?" He said: "Death."