Sahih Muslim Book 26, Hadith Number 5500.

Chapter : Plague, ill omen and magic.

Shu’ba reported from Habib: While we were in Medina we heard of plague having broken out in Kufa. ‘Ata b. Yasir and others said to me that Allah’s Messenger (may peace be upon him) had said. If you are in a land where it (this scourge) has broken out, don’t get out of it, and if you were to know that it had broken (in another land, then don’t enter it. I said to him: From whom (did you hear it)? They said: ‘Amir b. Sa’d has narrated it. So I came to him. They said that he was not present there. So I met his brother Ibrahim b. Sa’d and asked him. He said: I bear testimony to the fact that Usama narrated it to Sa’d saying: I heard Allah’s Messenger (may peace be upon him) as saying that it is a God-sent punishment from the calamity or from the remnant of the calamity with which people were afflicted before you. So when it is in a land and you are there, don’t get out of it, and if (this news reaches you) that it has broken out in a land, then don’t enter therein. Habib said: I said to Ibrahim: Did you hear Usama narrating it to Sa’d and he was not denying it. He said: Yes.