1The LORD dealt with Sarah as he had said, and the LORD did for Sarah as he had promised. 2Sarah conceived and bore Abraham a son in his old age, at the time of which God had spoken to him. 3Abraham gave the name Isaac to his son whom Sarah bore him. 4And Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. 5Abraham was a hundred years old when his son Isaac was born to him.6Now Sarah said, "God has brought laughter for me; everyone who hears will laugh with me." 7And she said, "Who would ever have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age."
8The child grew, and was weaned; and Abraham made a great feast on the day that Isaac was weaned. 9But Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, playing with her son Isaac. 10So she said to Abraham, "Cast out this slave woman with her son; for the son of this slave woman shall not inherit along with my son Isaac." 11The matter was very distressing to Abraham on account of his son. 12But God said to Abraham, "Do not be distressed because of the boy and because of your slave woman; whatever Sarah says to you, do as she tells you, for it is through Isaac that offspring shall be named for you. 13As for the son of the slave woman, I will make a nation of him also, because he is your offspring." 14So Abraham rose early in the morning, and took bread and a skin of water, and gave it to Hagar, putting it on her shoulder, along with the child, and sent her away. And she departed, and wandered about in the wilderness of Beer-sheba.
15When the water in the skin was gone, she cast the child under one of the bushes. 16Then she went and sat down opposite him a good way off, about the distance of a bowshot; for she said, "Do not let me look on the death of the child." And as she sat opposite him, she lifted up her voice and wept. 17And God heard the voice of the boy; and the angel of God called to Hagar from heaven, and said to her, "What troubles you, Hagar? Do not be afraid; for God has heard the voice of the boy where he is. 18Come, lift up the boy and hold him fast with your hand, for I will make a great nation of him." 19Then God opened her eyes and she saw a well of water. She went, and filled the skin with water, and gave the boy a drink.
20God was with the boy, and he grew up; he lived in the wilderness, and became an expert with the bow.21He lived in the wilderness of Paran; and his mother got a wife for him from the land of Egypt.
The Grace of the Living God is Wide.
The lineage that Jews and Christians follow in terms of God's covenantal promise and fulfillment, eventually leading to Jesus, is the line from Abraham, to Isaac, to Jacob, etcetera. Jews and Christians do not believe God's covenantal promise and fulfillment follow along the line going through Ishmael.
Muslims, on the other hand, believe that the true promise and fulfillment of God (Allah) goes through Ishmael. In fact, they think that Abraham was asked to sacrifice Ishmael and not Isaac (the Quran describing the sacrifice as the offering of Abraham's first-born son).
Therefore, in Islamic eyes, it's the figure of Ishmael who's the true recipient of the promises made to Abraham.
The person of Abraham is the foundational figure for Judaism, Christianity, and Islam. Their respective stories of God's saving acts in history, however, diverge at different points. The point of divergence for Jews and Christians is Jesus the Messiah. The point of divergence for Muslims happened much earlier, at the time of Isaac and Ishmael.
Although most Muslims claim to trace their history back to Ishmael, claiming that Muhammad was a descendant of Ishmael, the truth of the matter is that it's impossible to establish any clear link. Even the oft cited claim that Arabs are descendants of Ishmael is difficult to establish in any unproblematic way. At most we can say that some Arabs in the Arabian Peninsula may be descendants of Ishmael but not all Arabs since "Arabs" as a people group come from many smaller people groups with no relationship to Ishmael at all.
In the final analysis, one's genetic hereditary lines are not all that important in terms of our relationship to God. All of us, regardless of our ancestral lines, must come to God the Father, through Jesus, the Son of God, in order for us to have eternal life. Arguing about lineage is ultimately useless.
More important than one's lineage is God's grace.
What is the scope of God's grace? How wide is this grace? Does it only cover God's covenantal people, or does it extend to non-covenantal people? And what kind of grace are we talking about?
We can distinguish God's salvific grace which brings about the new birth in Christ and God's common grace which displays God's compassion toward humanity in general, without any necessary connection to salvation.
What is shown in the above passage is the compassion and care that God displays for Hagar and her son, Ishmael. They are not abandoned by YHWH, even though Sarah wants them banned. Furthermore, God commits to Ishmael that "a great nation" will come out of him. This is God's common grace -- the grace that expresses God's care and compassion and the grace that blesses.
The Good News of Jesus Christ still carries God's salvific grace and it's important that those who know Jesus share this good news. It's also important to remind ourselves that God's common grace is always at work on behalf of all people, the grace that displays God's mercy and love. Like those 3D glasses you get for 3D movies or for interactive rides, we see better with grace-filled 3D glasses with the lens of salvific grace and the lens of common grace.
Let's pray: Father God, we pray for Muslims around the world, that many, many will come to know the saving grace of your salvation in Jesus, the Son of God, who died and rose again from the dead, the One who defeated the powers of evil and overcame the barrier of sin. Have mercy on them. We also pray for ourselves that you might train our eyes to see the world as you would have us see: full of truth and compassion. That the Good News of Jesus makes the ultimate difference in people's lives while at the same time you continue to care for people as those created in Your Image. Teach us how to pray and teach us how to see. In Jesus' name, amen.