Musnad Abu Ya'la al-Mawsili 3:170

'Abd al-A'la ibn Hammad al-Narsi narrated to us, Hammad ibn Shu'ayb narrated to us, from Habib ibn Abi Thabit, from Tha'labah ibn Yazid al-Sa'di, who said: I heard 'Ali saying: The Messenger of Allah (may Allah bless him and grant him peace) said: "There is no Safar, no Hamah, and no contagion of a healthy person by a sick one." He said: So I said, "Did you hear it?" He said, "Yes, my two ears heard it and my two eyes saw it."