As the mater of fact for monks to stay in one place during the rainy season, the faithful devotees began to build monasteries and invited the monks to dwell in their monasteries in the hope of doing many meritorious and religious activities by offering meals for monks, observing precepts, listening to regular Dhamma sermon, and practising meditation and so forth.
The observation of the vassavasa retreat was brought great benefit to both monks and laymen. This retreat also has important and valuable consequences for the practice of Buddhist devotions and for the spiritual development to the monks and devotees as well. During the vassana period generally the monks spend their time either in meditation and study or teaching or instructing the laity on various aspects of the Buddha Dhamma and encourage their lay disciples to practice the doctrine. In this way the lay people accumulate lot of merits by inviting monks for rainy retreats at monasteries and providing monks for their basic necessities of food, robes medicine and dwelling places during the rainy season.
Establishment of permanent resident or aramas (dwellings) for monks started as a result of the ideal friendship maintained in between monks and lay followers during the rainy retreat. Later on these monasteries became great centres of learning and propagation of the Buddha Dhamma.