Yagya has been a part of an individual or social ritual since the Vedic times. When the ritual fire – the divine Agni, the god of fire and the messenger of gods – are deployed in a yagya, mantras are chanted. The hymns and songs sung and oblations offered into the fire are a form of hospitality towards the Vedic gods. The offerings are carried by Agni (fire) to the gods, the gods in return are expected to grant boons and benedictions, and thus the ritual served as a means of spiritual exchange between gods and human beings. Yagya is a large scale ritual lasting over several days and involves daily oblations in the sacred fire. It can be either performed by a few priests over multiple days or several priests performing in a single day. Many people use the yagna or yajna words instead of yagya, the meaning of it is the same. Yagyas are done by highly learned vedic pandits, who are the experts of vedic ceremonies and who live their lives' according to the rules of vedic tradition.