According to the Book of Genesis, Ishmaelites are the descendants of Ishmael, the elder son of Abraham and the descendants of the twelve sons and princes of Ishmael. Throughout history, the Ishmaelites have been associated with Arabs. Indeed, two prominent North Arabian tribes, the Qedarites and Nabateans, have names corresponding to two of Ishmael's sons. The original sequence of events, who called whom which name first and how this relates to the tradition of Abraham as a patriarch and forefather is unclear. Even today, many call upon Ishmael as their people's ancestor, notably Muslim Arabs.
According to the Book of Genesis, Abraham's first wife was named Sarah and her Egyptian slave was named Hagar. However Sarah could not conceive. In chapter 16 Sarah gave her slave Hagar in marriage to Abraham, in order that Abraham might have an heir. Hagar conceived Ishmael from Abraham, and the Ishmaelites descend from him. After Abraham pleaded with God for Ishmael to live under his blessing, chapter 17 states: Chapter 25 lists his sons as:
The Targum Onkelos annotates Genesis 25:16, describing the extent of their settlements: "And they dwelt from Hindekaia unto Chalutsa, which is by the side of Mizraim, from thy going up towards Arthur."
Quran
"Allah has gifted all of Ishmael, Elisha, Jonah and Lot a favour above the nations.
With some of their forefathers and their offspring and their brethren; and We chose them and guided them unto a straight path".
Kebra Nagast
The 14th centuryKebra Nagast says "And therefore the children of Ishmael became kings over Tereb, and over Kebet, and over Nôbâ, and Sôba, and Kuergue, and Kîfî, and Mâkâ, and Môrnâ, and Fînḳânâ, and ’Arsîbânâ, and Lîbâ, and Mase'a, for they were the seed of Shem."
Genealogical attempt to trace the ancestry of the Arabs
Medieval Arab genealogists divided Arabs into three groups:
"Ancient Arabs", tribes that had vanished or been destroyed, such as ʿĀd and Thamud, often mentioned in the Qur'an as examples of God's power to destroy those who did not believe and follow their prophets and messengers.
"Pure Arabs" of South Arabia, descending from Qahtan son of Hud. Some of the Qahtanites are said to have migrated from the land of Yemen following the destruction of the Ma'rib Dam.
The "Arabized Arabs" of center and North Arabia, descending from Ishmael the elder son of Abraham through his descendant Adnan. Such as the ancient tribe of Hawazin, or the modern-day tribes of Otaibah and Anazzah.
Abu Ja'far al-Baqir wrote that his father Ali ibn Husayn informed him that prophet Muhammad had said: "The first whose tongue spoke in clear Arabic was Ishmael, when he was fourteen years old." Hisham Ibn Muhammad al-Kalbi established a genealogical link between Ishmael and Muhammad using writings and the ancient oral traditions of the Arabs. His book, Jamharat al-Nasab, seems to posit that the people known as 'Arabs' were all descendants of Ishmael. Ibn Kathir writes, "All the Arabs of the Hijaz are descendants of Nebaioth and Qedar." Medieval Jewish sources also usually identified Qedar with Arabs and Muslims. According to author and scholar Irfan Shahîd, while Western scholars viewed this kind of "genealogical Ishmaelism" with suspicion, the concept can be supported,
Genealogical Ishmaelism was viewed with suspicion as a late Islamic fabrication because of the confusion in Islamic times which made it such a capacious term as to include the inhabitants of the south as well as the north of the Arabian Peninsula. But short of this extravagance, the concept is much more modest in its denotation, and in the sober sources it applies only to certain groups among the Arabs of pre-Islamic times. Some important statements to this effect were made by Muhammad when he identified some Arabs as Ishmaelites and others as not.
Ishmaelism in this more limited definition holds that Ishmael was both an important religious figure and eponymous ancestor for some of the Arabs of western Arabia. Prominence is given in Arab genealogical accounts to the first two of Ishmael's twelve sons, Nebaioth and Qedar, who are also prominently featured in the Genesis account. It is likely that they and their tribes lived in northwestern Arabia and were historically the most important of the twelve Ishmaelite tribes. It is believed that the first person to speak Arabic clearly was Ishmael from Greek literature sources: "Isma’il grew up among the Jurhum an Arabic speaking tribe, learning the pure Arabic tongue from them. When grown up he successively married two ladies from the Jurhum tribe, the second wife being the daughter of Mudad ibn ‘Amr, leader of the Jurhum tribe." In accounts tracing the ancestry of Muhammad back to Ma'ad, Arab scholars alternate, with some citing the line as through Nebaioth, others Qedar. Many Muslim scholars see Isaiah 42 as predicting the coming of a servant of God who is associated with Qedar and interpret this as a reference to Muhammad.