Elkasites were members of an ancient Jewish sect, whose name was taken from its founder, Elxai .
The ancient historian Josephus, in History of the Jewish Wars (ca 75 CE) defined three philosophical sects of contemporary Judaism:
- "For there are three philosophical sects among the Jews. The followers of the first of whom are the Pharisees; of the second the Sadducees, and the third sect, who pretends to a severer discipline, are called Essenes."
Josephus further elaborates on the Essene sect by saying that it is divided into two separate orders: "Moreover, there is another order of Essenes, who agree with the rest as to their way of living and customs and laws but differ from them in the point of marriage."
Elxai was a prophet of the Essene Occaean sect. He was also later accepted by the Nazarenes and some Ebionites who came after him. While Ossaeans had been celibate up to this point in time, Elxai himself was married and, in fact, seems to have reversed this doctrine, since he successfully encouraged marriage within the sect, possibly even insisting on it.
He introduced the oaths to the substances of salt, water, earth, bread, heaven, aether, and wind; with seven “witnesses”: sky, water, holy spirits, angels of
prayer, the olive, salt, and earth.
He further taught the rejection of the "false Law of Moses."