Abraham is the father, in type, of a new spiritual race, and those in Christ are his seed and heirs according to the promise (Galatians 3:26-29). Membership in this family does not depend on blood descent, race, gender, or social status, but on being in Christ through faith, repentance, and baptism. Like Isaac, who was born by God's miraculous promise rather than natural processes, Christians are children of promise, made so by God's call and election, not by their own ability (Romans 9:6-9). Because God loves Abraham as His friend, Abraham's descendants receive benefits for his sake, including the Bible entrusted to Israel. Physical descent or a mere claim to Abraham as father profits nothing. The Jews who sought to kill Jesus were Abraham's physical descendants, yet their rejection of God's word proved Satan was their spiritual father (John 8:37-44). True children of Abraham share his spirit of trusting and submitting to God's word, and that faith produces his works. As new creations, they reject the ways of their former spiritual father. Like Abraham, they are called out and separated from the world, and they live as strangers and pilgrims whose lives are unsettled and require sacrifice. They content themselves with God alone, looking for a city whose builder is God. What Abraham cherished above land or reward was his relationship with God, and his children must cultivate that same friendship through prayer, Bible study, and trusting obedience.

Abraham's children include more than Isaac and the sons of Hagar and the concubines. Before Genesis 12, Abram and Suzanna, an Assyrian descended from Shem through Asshur, had a son named Achaim, born around 1902 BC. When Abraham sent the concubines' sons eastward away from Isaac, as Genesis 25:6 and 21 record, Suzanna and Achaim were sent back to Assyria and then to the Danube Valley, where they ruled. Achaim reigned forty-five years, married a Hungarian princess, and had four children. By sending them away, Abraham gave up any claim to the Austrian throne. Through this line a Semitic culture arose in Austria and Hungary, uniting the Assyrian branch from Asshur with the Hebrew branch from Arphaxad through Eber to Abraham. Hagar's son Ishmael was sent away with her, yet God promised to make a nation of him because he is Abraham's seed, while the covenant line runs through Isaac. Spiritually, Abraham is father of the faithful, and the promise does not come through the law but through the righteousness of faith. All who are baptized into Christ and belong to Him are Abraham's seed and heirs according to the promise, whether Jew or Greek, slave or free, male or female. Christ's life and death confirmed the promises, so Abraham will inherit the world and believers are co-heirs with him and with Christ.

Isaac, the son of promise and Abraham's only legitimate son, is the child through whom God's promises to Abraham run, and Abraham's love for him was never wrong so long as it did not become worship or displace God. When God commanded Abraham to offer Isaac on Moriah, Abraham obeyed without hesitation, having reasoned, as Hebrews 11:19 says, that the promises required Isaac and that God could raise him. Isaac was a young man, probably about 33, while Abraham was about 133. Abraham could bind him only because Isaac submitted willingly, trusting his father and God. Abraham is a type of God the Father, and Isaac a type of Christ: he carried the wood up the mountain and went humbly to the altar. The ram caught in the thicket, offered in his place, pictures Christ offered for us. Because Abraham withheld neither his son nor himself from God and so proved he had no other gods, God swore by Himself to bless him and multiply his descendants like the stars and the sand. The physical promise became unconditional, and in his seed all nations would be blessed. The peace and prosperity of Abraham's physical descendants today rest on that promise. Both the physical and the spiritual outcomes depended on Abraham and Isaac putting God first.