Illegitimate: not carried out, made, or constituted in accordance with the law, the rules governing a particular activity, or social norms and customs.

Abraham’s illegitimate son with Hagar was Ishmael. Illegitimate in the sense of the above definition “not in accordance with the law.” The law in this case was the Covenant promise from God of a descendent from Abraham through Sarah. God’s promise for decedents composing an everlasting Nation of God was also from Abraham through Sarah. A child to any other wife was not a legitimate child of the Covenant law promise. Muhammad attempted to claim that he was a decedent of Ishmael along with all his followers. True, Ishmael was born first before Isaac, but according to the Covenant law promise in the Bible, Ishmael was not a legitimate son of the covenant promise to Abraham. Isaac was born legitimately according to the “rules of a particular activity” –God’s Word and promise. This is the promise of God to Ishmael. “You shall call his name Ishmael, because the Lord has heard you affliction. He shall be a wild man; His hand shall be against every man, and every man’s hand against him.” Genesis 16:4. The true story of Ishmael and Isaac can be found in the Bible in Genesis, Chapters 16 & 17.