Jews = children of Abraham through Isaac.
Muslims = children of Abraham through Ismael.
Christians = children of Abraham through Jesus.

Abraham serves as an example.  He believed God, and that faith was regarded as the basis of Abraham’s approval by God.  You must understand that people who have faith are Abraham’s descendants. Scripture saw ahead of time that God would give his approval to non-Jewish people who have faith.  So Scripture announced the Good News to Abraham ahead of time when it said, “Through you all the people of the world will be blessed.”  So people who believe are blessed together with Abraham, the man of faith.
(Galatians 3:6-9 -- GW)