The word ‘promise’ in the Biblical context is a legal term meaning to graciously do or give something. In other words a promise is a unilateral commitment made voluntarily; not the result of negotiations.
God first made an extensive promise to Ishmael, the son of Abraham through Hagar.
“Then the Angel of the LORD said to her (Hagar), ‘I will multiply your descendants exceedingly, so that they shall not be counted for multitude… Behold, you are with child, and you shall bear a son. You shall call his name Ishmael, because the LORD has heard your affliction. He shall be a wild man; his hand shall be against every man, and every man’s hand against him. And he shall dwell in the presence of all his brethren’.” Genesis 16:10-12
The Hebrew for ‘wild’ translates to a wild donkey, or onager. Such were very aggressive and independent. Onagers were further described by God in the Book of Job.
“Who set the wild donkey free? Who loosed the bonds of the onager, whose home I have made the wilderness, and barren land his dwelling? He scorns the tumult of the city; he does not heed the shouts of the driver. The range of the mountains is his pasture…” Job 39:5-8
God then proclaimed that Ishmael would be the beginning of a great nation.
“And as for Ishmael, I have heard you. Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly. He shall beget twelve princes, and I will make him a great nation.” Genesis 17:20
When Hagar and Ishmael were ‘cast out’ from the presence of Abraham and Sarah, Abraham was given more details of the future of Ishmael.
“Yet I will also make a nation of the son of the bondwoman, because he is your seed.” Genesis 21:13
Likewise when Hagar and Ishmael were in the desert, Hagar was told of Ishmael’s future.
“…Then the angel of God called to Hagar out of heaven, and said to her…’Fear not, for God has heard the voice of the lad… I will make him a great nation’.” Genesis 21:17-18
Ishmael and his descendants would be the beginning of the Arab nations.
“Now this is the genealogy of Ishmael, Abraham’s son, whom Hagar the Egyptian, Sarah’s maidservant, bore to Abraham…Nebajoth; then Kedar, Adbeel, Mibsam, Mishma, Dumah, Massa, Hadar, Tema, Jetur, Naphish, and Kedemah. These were the sons of Ishmael… twelve princes according to their nations.” Genesis 25:12-16
The Bible explicitly explains that the promise to Ishmael is totally different than the promise to Isaac. God told Abraham the following relative to Sarah and their future son Isaac that she would bear.
“And I will bless her and also give you a son by her; then I will bless her, and she shall be a mother of nations; kings of peoples shall be from her. Genesis 17:16
It was at this point that Abraham laughed at God’s word inasmuch as Abraham was 100 years old and Sarah was 90. Abraham suggested that his son Ishmael already born of Hagar be the heir of the covenant.
“Then God said: ‘No, Sarah your wife shall bear you a son, and you shall call his name Isaac; I will establish My covenant with him for an everlasting covenant, and with his descendants after him’.” Genesis 17:19
God then reiterated His promise relative to Isaac.
“But My covenant I will establish with Isaac, whom Sarah shall bear to you at this set time next year.” Genesis 17:21
The different promises made to Isaac and Ishmael constitute one of the major doctrines of the New Testament. The two promises, in fact, define the two basic categories of all mankind.
The son born of the flesh (Ishmael) represents the attempt to attain salvation by works while the son of promise (Isaac) represents the attainment of salvation by faith.
“For what does the Scripture say? ‘Abraham believed God, and it was accounted (imputed, credited) to him for righteousness’.” Romans 4:3
“Therefore we conclude that a man is justified (declared righteous) by faith apart from the deeds of the law.” Romans 3:28
Everyone has the freedom to choose…