Judaism, Christianity and Islam are called Abrahamic faiths because all three religions trace their roots back to Abraham (a father of many nations). The story of Abraham includes his two sons Ishmael and Isaac, who also play important roles in the founding of these faiths. It is likely Abraham’s narrative is a literary construct that does not relate to any period in actual history.
In Jewish tradition, Abraham (Abram) was born about 1800 BC and is regarded as the patriarch who established the Covenant (contract) between the Jewish people and God. He is regarded as both the biological progenitor of the Jews (the first Jew), and the father of Judaism.
Abraham is often mentioned in the Qur’an. He is called a monotheist (believes there is only one God), a Muslim (one who submits to God), a patriarch, and a prophet. Mohamed depicts Abraham as the perfect Muslim. In Islamic tradition, Isaac is revered as a prophet of Islam, and the father of the Israelite's. Abraham’s oldest son Ishmael is regarded as the ancestor of the Arabs. Abraham and Ishmael journeyed to Mecca to build Islam’s Holy shrine the Kaaba, and Ishmael, along with his mother Hagar are thought to be buried next to the shrine. The Qur'an commands Muslims to believe in the revelations given to "Abraham, Ishmael, Isaac, Jacob and the Patriarchs".
For Christians, Jesus is the Messiah who brings God’s message to humanity. Abraham is recognized as the first person to believe in a single powerful God (monotheism), and his son Isaac links Abraham to Christian tradition. The divinity of Jesus is a key construct of Christian theology that separates Judaism and Islam from Christianity. In Judaism and Islam, Jesus is not regarded as being divine and is only seen as one of many prophets.
Judaism holds that one becomes a descendant of Abraham through birth. Christians theoretically believe one becomes a descendant of Abraham through faith. Islam holds that one becomes a descendant of Abraham through both birth and faith. Because Islam draws much of its tradition from the Old Testament, many of its beliefs are similar to those found in Jewish literature.