Musnad Ahmad 944:11

Waki’ narrated to us, from Sufyan, from Habib ibn Abi Thabit, from Ibrahim ibn Sa’d, from Sa’d ibn Malik, and Khuzaymah ibn Thabit, and Usamah ibn Zayd, they said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The plague is a scourge or a punishment with which a people were punished. So if it occurs in a land and you are in it, do not exit from it, and if you hear of it in a land, do not enter upon it."