No, this article isn’t really about Hagar. But the next generation faced a strikingly similar situation. Surely Isaac knew that the Lord had said to his father Abraham, “Through Isaac your descendants will be counted” (Gen 21:12). But Isaac was pushing 60 and still had no children. The promised seed didn’t look too promising. The barrenness that had afflicted his mother Sarai (11:30) now clung to his wife Rebekah (25:21). And the blessing of Rebekah’s family, “May you become the mother of thousands of ten thousands!” (24:60), was sounding more and more like mere wishful thinking. Nearly 20 years had passed since Isaac and Rebekah were married but there was still no crib in their tent. Were they tempted to give the Hagar approach a try?
Interestingly, the verses preceding our narrative indicate just how fruitful Hagar’s son Ishmael had become. The non-chosen line ended up having 12 princes (25:12-18). The chosen line of Isaac couldn’t even get a line started.
If it looks like a replay of Genesis 16, it is. The mention of Abraham throughout chapter 25 gets us thinking about God’s promises to him and his seed. The references to Hagar, Sarah and Ishmael (vv12-18) take us back to the faithless decision Abraham and Sarah made decades before. Isaac and Rebekah’s lengthy period of childlessness is also highlighted (vv20-21). The resemblance to Genesis 16 is uncanny, but with one admirable exception – Isaac’s response. He “prayed to the LORD on behalf of his wife because she was childless” (v21). Abraham didn’t pray; his son did. It is likely that Isaac’s praying occurred throughout those 20 years, not merely at the climax of them. His faith in the promises of God was steady and strong, and he knew he had every right to pray for a child since it was in keeping with God’s promises. There were likely days when he and Rebekah were tempted to give up and take matters into their own hands as did the previous generation, but they shunned the Hagar approach, remaining remarkably resolute in their faith.
The result was that “the LORD answered his [Isaac’s] prayer, and his wife Rebekah became pregnant” (v21). And God’s answer came not with a son, but two.
As believers now living in a different age, the same temptation to adopt the Hagar approach is always just lingering around the corner. We don’t like waiting. And we tend to view waiting as wasting time. The alluring call to move ahead of God tests every generation, but divine promises can only be fulfilled by the One who gives them. Waiting on the Lord is no fruitless exercise but draws us closer to the One who brings His promises to pass in His time. Isaac and Rebekah may have already learned from his parents that running ahead of God won’t make Him run any faster, for they still had to wait 14 more years after Ishmael’s birth for the promised son’s arrival. No one changes God’s schedule, including you. So pray, wait, and let God do His work in His time. He doesn’t want a helping hand, only a trusting heart.
 Bible quotations in this article are from the NET.
 We should also note Rebekah’s commendable practice of bringing her need to the Lord (25:22-23).
 Isaac wins the honorable title of being the only monogamous patriarch.