Abraham had one son that was alive to God. He had eight sons all together but only one was begotten.
Hebrews 11:17By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son.
Genesis 17:15And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be. 16And I will bless her, and give thee a son also of her: yea, I will bless her, and she shall be a mother of nations; kings of people shall be of her. 17Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear? 18And Abraham said unto God, O that Ishmael might live before thee! 19And God said, Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him. 20And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation. 21But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year. 22And he left off talking with him, and God went up from Abraham.
Ishmeal was given an earthy covenant because of the exchanged life. Abraham had a covenant with God and God honoured it with an earthly covenant with Ishmael. Of course the consequences of it are the entire middle east problem.
Ephesian 2:11Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands; 12That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world: 13But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ. 14For he is our peace, who hath made both one, and hath broken down the middle wall of partition between us; 15Having abolished in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace; 16And that he might reconcile both unto God in one body by the cross, having slain the enmity thereby: 17And came and preached peace to you which were afar off, and to them that were nigh. 18For through him we both have access by one Spirit unto the Father.