Is it permissible to sit in seclusion in a cave as the Sufis did?

Answer

It is permissible to sit in seclusion in caves as many Auliya had done. Jamaa't Salaat is Waajib on those who live in a community. It is not Waajib on a traveler nor on one living alone in a wilderness or a cave which is outside the city precincts. Jumuah Salaat is compulsory on a resident of the city, not on those living in villages and in the wilderness.