Musnad Ahmad

It is narrated from Sayyiduna Abdur Rahman bin Sannah (may Allah be pleased with him) that he heard the Prophet (peace and blessings be upon him) say: Islam began as something strange, and it will become strange again as it began, so glad tidings are for the strangers. Someone asked: O Messenger of Allah! Who are the strangers? He said: Those who rectify (reform) when people become corrupt. By Him in Whose Hand is my soul, a time will surely come when faith will withdraw to Madinah just as a stream withdraws to its source. And by Him in Whose Hand is my soul, Islam will enter between the two mosques just as a snake enters its hole.