Sahih al-Bukhari 7125

Ibrahim related from Abu Bakra that the Prophet, may Allah bless him and grant him peace, said, "The terror of the false Messiah (Dajjal) will not enter Madina. At that time it will have seven gates, with two angels at each gate." Salih ibn Ibrahim related that his father said, "I came to Basra and Abu Bakra told me that he heard the Prophet, may Allah bless him and grant him peace, say this." It is related from Abu Bakra that the Prophet, may Allah bless him and grant him peace, said, "The terror of false Messiah (Dajjal) will not enter Madina. At that time it will have seven gates, with two angels at each gate."