Sahih Bukhari | Volume 9 | Hadith Number 181
Narrated by Zainab bint Jahsh
The Prophet got up from his sleep with a flushed red face and said, "None has the right to be worshipped but Allah. Woe to the Arabs, from the Great evil that is nearly approaching them. Today a gap has been made in the wall of Gog and Magog like this." (Sufyan illustrated by this forming the number 90 or 100 with his fingers.) It was asked, "Shall we be destroyed though there are righteous people among us?" The Prophet said, "Yes, if evil increased."