It is not the children of the flesh that are the children of God, but the children of promise are reckoned as seed.
This is Paul’s comment on the story of the birth of Ishmael and Isaac (Genesis 16; 17:15-21; 18:9-15; 21:1-7). The whole story fills me with longing not to build a “successful” church with multiplied Ishmaels.
Here’s what I mean. God promised Abraham “your own son will be your heir” (15:4). As the stars “so shall your descendents be” (15:6). But Sarah, his wife, was barren (11:30). She “bore him no children” (16:1).
Picture Abraham as a pastor. The Lord says, “I will bless you and prosper your ministry.” But after a time there is little fruit. The church is barren and bears no children.
What does Abraham do? He begins to despair of supernatural intervention. He is getting old. His wife remains barren. So he decides to bring about God’s promised son without supernatural intervention. He has sex with Hagar his wife’s handmaid (16:4). However the result is not a “child of promise,” but a “child of the flesh,” Ishmael.
God stuns Abraham by saying, “I will give you a son by Sarah” (17:6). So Abraham cries out to God, “O that Ishmael might live in your sight” (17:18). He wants the work of his own flesh to be the fulfillment of God’s promise. But God says, “No, but Sarah your wife shall bear you a son” (17:19).
But Sarah is now 90 years old. She has been barren all her life, and now she no longer menstruates (18:11). Abraham is 100. God has put off the promise so long it is now humanly impossible. The only hope for a child of promise is supernatural intervention.
That is what it means to be a “child of promise”—to be born “not by the will of the flesh, nor by the will of man, but of God” (John 1:13). The only children that count for children of God in this world are supernaturally begotten children of promise. That’s the point of this Old Testament text. In Galatians 4:28 Paul says, “You [Christians], like Isaac, are children of promise.” You are “born according to the Spirit, not according to the flesh” (4:29).
Think of Abraham as a pastor again. His church is not growing the way he believes God promised. He is weary of waiting for supernatural intervention. What does he do? He turns to the “Hagar” of mere human devices and decides he can “attract people” without the supernatural work of the Holy Spirit.
And he can. However, it will not be a church of Isaacs, but Ishmaelites—children of the flesh, not children of God. God save us from this kind of success. How will he? By moving us to build our ministry around prayer (and fasting).
Persevering until the supernatural intervention,