Musnad Ahmad 30:2598

Waki' and Abu Nu'aym—who is al-Fadl ibn Dukayn—narrated to us, they said: Sufyan narrated to us, from Suhayl ibn Abi Salih, from his father, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If you meet the Jews on the road, then force them to its narrowest part, and do not initiate the greeting with them." Abu Nu'aym said: "The polytheists on the road."