Verily the faith would recede to Medina just as the serpent crawls back into its hole.
Sahih Muslim Book 1, Hadith 281
← Previous Hadith Verily Islam started as something strange and it would again revert (to its old position) of being strange just as it started, and it would recede between the two mosques just as the serpent crawls back into its hole.

Sahih Muslim Book 1, Hadith 280 Next Hadith → "The Hour (Resurrection) will not occur until 'Allah, Allah' is not said on earth."

Sahih Muslim Book 1, Hadith 282