Vas Invitation ( Monks were invited to resite at the monastery for the rainy season )

As a part of the Buddha’s teachings, each monk should reside at a one place in the rainy season. In India it was July to October. Now every monk takes that tredition and stays in a one monastery for the season. People used to invite monks when the met them to reside in their village so they can offer food and other nessesory things to monks.