Musnad Abu Ya'la al-Mawsili 3:171

Uthman ibn Abi Shaybah and Ibn Numayr informed us, they said: Al-Walid ibn Uqbah narrated to us—Uthman al-Shaybani said: Hamzah al-Zayyat narrated to us, from Habib ibn Abi Thabit, from Tha'labah, in the hadith of Uthman al-Humani—from Ali, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no Safar, no Hamah, and no healthy one infects a sick one."