Musnad Ahmad 32:1765

'Affan narrated to us, 'Abd al-Wahid ibn Ziyad narrated to us, 'Asim al-Ahwal narrated to us, he said: Hafsa bint Sirin narrated to me, she said: Anas ibn Malik said to me: "What did Yahya ibn Abi 'Amra die of?" I said: "Of the plague." Anas ibn Malik said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The plague is martyrdom for every Muslim."