Explanation:

The Vinaya Pitaka is a Buddhist scripture, one of the three parts that make up the Tripitaka. Its primary subject matter is the monastic rules for monks and nuns. It was compiled at the First Council shortly after the Buddha's death, and recited by Upali, with little later addition.
According to the scriptures, in the first years of the Buddha's teaching the sangha lived together in harmony with no vinaya, as there was no need, because all of the Buddha's early disciples were highly realized if not fully enlightened. As the sangha expanded situations arose which the Buddha and the lay community felt were inappropriate for samanas. Sutta Pitaka is the collection of sermons of Buddha.