Christianity, Islam, and Judaism are the largest Abrahamic religions in terms of numbers of adherents. Abrahamic religions with fewer adherents include the faiths descended from Yazdânism (the Yezidi, Yarsani and Alevi faiths), Samaritanism, the Druze faith (often classified as a branch of Isma'ili Shi'i Islam), Bábism, the Bahá'í Faith and Rastafari.
As of 2005, estimates classified 54% (3.6 billion people) of the world's population as adherents of an Abrahamic religion, about 32% as adherents of other religions, and 16% as adherents of no organized religion. Christianity claims 33% of the world's population, Islam has 21%, Judaism has 0.2% and the Bahá'í Faith represents around 0.1%.
It was suggested by Louis Massignon that the phrase, "Abrahamic religion" means that all these religions come from one spiritual source. Paul referred to Abraham as the "father of us all". There is a Quranic term, millat Ibrahim 'religion of Ibrahim', indicating that Islam sees itself as standing in a tradition of religious practice from Abraham. Jewish tradition claims that the Jews are descended from Abraham, and adherents of Judaism derive their spiritual identity from Abraham as the first of the three "fathers" or biblical Patriarchs: Abraham, Isaac, and Jacob.
All the major Abrahamic religions claim a direct lineage to Abraham, although in Christianity this is understood in spiritual terms:
Other terms sometimes used include Abrahamic faiths, Abrahamic traditions, religions of Abraham, Abrahamic monotheistic religions, Semitic religions, Semitic monotheistic religions, and Semitic one god religions.