Sahih Muslim 147
Sahih Muslim · Book 1: The Book of Faith · Clarifying that Islam started as something strange, and will revert to being something strange, and it will retreat between the two Masajid
It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) said:
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ ، وَأَبُو أُسَامَةَ عَنْ عُبَيْدِ اللَّهِ بْنِ عُمَرَ ، ح وَحَدَّثَنَا ابْنُ نُمَيْرٍ ، حَدَّثَنَا أَبِي ، حَدَّثَنَا عُبَيْدُ اللَّهِ ، عَنْ خُبَيْبِ بْنِ عَبْدِ الرَّحْمَنِ ، عَنْ حَفْصِ بْنِ عَاصِمٍ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ الإِيمَانَ لَيَأْرِزُ إِلَى الْمَدِينَةِ كَمَا تَأْرِزُ الْحَيَّةُ إِلَى جُحْرِهَا " .
Verily the faith would recede to Medina just as the serpent crawls back into its hole.