Musnad Ahmad 10:11

Rawh narrated to us, Muhammad ibn Abi Hafsah narrated to us, al-Zuhri narrated to us, from Ubayd Allah ibn Abd Allah, from Ibn Abbas, who said: I heard Abd al-Rahman ibn Awf saying: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "If the plague is in a land and you are not in it, then do not enter it. And if it is in a land and you are in it, then do not exit from it."