Judaism, Christianity, and Islam (as well as the Baha'i Faith) comprise a family of religions. A number of terms recognize their historico-theological links: the popular label "Peoples of the Book" underlines the central role scripture plays among their adherents, while scholars of religion sometimes categorize them as the "three major monotheistic faiths." The term "Abrahamic" has advantages over both usages; it focuses on a more specific affinity than does the first and avoids the categorical and interpretive controversies that may arise over the second while emphasizing the paramount place that Abraham holds in all three traditions.
For Jews, Abraham is, through Isaac and Jacob, the founding patriarch of the Children of Israel, the person to whom God promises "I will make of you a great nation/And I will bless you" (Gen. 12:2) and with whom He enters into "an everlasting covenant throughout the ages to be God to you and to your offspring to come" (Gen. 17:7). For Christians, he is the progenitor through whose seed, Jesus, God's blessings descend to the faithful, the grantee of God's covenanted promise---"those who believe are blessed with Abraham who believed" (Gal. 3:9)---and a spiritual exemplar who "grew strong in his faith as he gave glory to God" (Ro. 4:20). For Muslims, he is a prophet, a Friend of God who stands in the line of those---from Noah to Muhammad---to whom Allah gave revelations (Qur'an 4:163), and who "raised the foundations of the House" [i.e., the Ka'aba] (Qur'an 2:127) with his first son, Isma'il.
Even as they all acknowledge Abraham as an ancestor, members of the three traditions have also tried to claim him as exclusively theirs. The Lubar Institute is dedicated to examining both the commonalities among the traditions and their disputes, as well as encouraging members of those traditions to consider their shared Abrahamic legacies.