Sahih Muslim Book 26, Hadith Number 5496.

Chapter : Plague, ill omen and magic.

‘Amir b. Sa’d reported that a person asked Sa’d b. Abu Waqqas about the plague, whereupon Usama b. Zaid said: I would inform you about it. The Messenger of Allah (may peace be upon him) said: It is a calamity or a disease which Allah sent to a group of Bani Isra’il, or to the people who were before you; so when you hear of it in land, don’t enter it and when it has broken out in your land, don’t run away from it.