Adyton Incubation

The adyton(Greek: Άδυτον) or adytum (latin) was a restricted area within the cella of a Greek or Roman temple. Its name meant "inaccessible" or "do not enter". The adyton was frequently a small area at the farthest end of the cella from the entrance: at Delphi it measured just nine by twelve feet. The adyton would often house the cult image of the god. Adyta were spaces reserved for oracles, priests or acolytes, and not for the general public. (source Wikipedia)

Incubation (Ritual), the religious practice of sleeping in a sacred area with the intention of experiencing a divinely inspired dream or cure. Incubation was practised by members of the cult of Asclepius. [...] Incubation was adopted by certain Christian sects and is still used in a few Greek monasteries. (source Wikipedia)