The patriarch of the monotheistic religions of Judaism, Christianity, Islam, and the Baha'i Faith is/was Abraham.
Abraham, Isaac, and Jacob.
Christianity, Judaism and Islam
Abraham because his son Isaac is another patriarch of Judaism but his other son Ishmael's descendants became the Arabs.
Abraham was the first patriarch of gods family.
The first great Patriarch of God's family is Abraham
Abraham founded Judaism. Christianity and Islam are daughter-religions of Judaism.See also the Related Links.Link: How Abraham founded JudaismLink: Was Islam's inception influenced by Judaism
Abraham
Abraham is called a patriarch because he was one of the three forefathers of the Israelite Nation.The definition of patriarch is: "One of the scriptural fathers of the human race or of the Hebrew people"
There is the patriarch and then there's the ecumenical patriarch. There are many partiarchs for each nationality of Orthodoxy and the ecumenical patriarch is the head of all Orthodox. He is not, though, like the Pope. The ecumenical patriarch is the "first among equals" and is by no means infallible.
Abraham
Patriarch