Answer.The Abrahamic Covenant is an all-embracing arrangement. Everything that God has done and will yet do for our race is included in that Abrahamic Covenant. The Law Covenant of Israel was added to this Covenant "because of trangression." Although only a typical arrangement, nevertheless the Law Covenant developed a certain faithful class, to be made "princes in all the earth" during the Millennial Age. This Covenant was represented by Hagar; and her son Ishmael represented the nation of Israel. (Galatians 4:21-31.) The Christ, the New Creation class, was represented in Isaac, Sarah's son. Sarah, Abraham's first wife, represented that part of the Abrahamic Covenant which pertained to the Spiritual Seed, the New Creation, that which we sometimes speak of as the Sarah Covenant. This Sarah Covenantthe Grace Covenant, the Covenant of Sacrifice (Psalm 50:5)brings forth the Isaac class, the Church, head and Body.
Even as Isaac was not born after the flesh in the ordinary sense (Abraham and Sarah being too old naturally), but was a special creation, so with The Christ company, the Church. This "Isaac" class is developed as a distinctly new creation, formed from members of the fallen human race. The Divine invitation to these is to present their bodies living sacrifices. They sacrifice their human nature that they may attain with their Head, the antitypical "Isaac" the Divine naturesomething never before offered. After this New Creation is completed, the blessing indicated in God's Promises to Abraham will reach all the families of the earth. It will teach them, first through the "Isaac" Seed, the New Creation, and secondly, through the Ancient Worthies developed in the Ages preceding this Age, under God's typical arrangements.
All kindreds and families of the earth will be blessed [R5909 : page 170] by the privilege or opportunity to become children of Abraham, children of God, whom Abraham represented in a figure. "I have made thee a father of many nations (Genesis 17:5; Romans 4:17), said the Lord to Abraham"In becoming thy seed shall all the nations of the earth bless themselves." These will be blessed under the New covenant, an arrangement whereby the Abrahamic Covenant will be fulfilled as relates to Israel and to all.
The Abrahamic Covenant, then, embraces all the other Covenants, those Covenants being merely different features of God's arrangements by which the work implied in the great Abrahamic Covenant or Promise is to be accomplished.
As we have elsewhere previously shown, Abraham took another wife, after the death of SarahKeturah. By her he had many sons and daughters. Thus the New Covenant is typed and its grand work of bringing many to lifeto "the liberty of the sons of God."Romans 8:19,21.