Of all the challenges to our faith, perhaps nothing is more difficult than to believe that our suffering fits into God’s gracious purposes for our lives. When we cry out to the Lord in prayer during our suffering, we are lamenting the fact that this world is not as it should be. God originally created humankind to live with him in paradise, but because of the rebellion of Adam and Eve, we now live in a broken, fallen, sinful world. Our suffering is the fruit of the presence of sin and death in the world. Therefore, suffering is evil, and God promises that he will personally wipe away the tears of suffering from our eyes forever when he brings us into the new heavens and the new earth (Rev. 21:4).

Even so, suffering does not run its course chaotically, unbridled, and out of control. If the Fall caused suffering to enter the world like a chaotic flood, God personally oversees and directs the channels, rivers, and streams where those floodwaters of suffering flow. He appoints boundaries to the chaos of suffering, declaring, “Thus far shall you come, and no farther, and here shall your proud waves be stayed!” (cf. Job 38:8–11). Though Satan himself rages against us, tossing the waves of suffering toward us, he cannot prevail; though he roars, suffering cannot pass over the boundaries God himself has appointed (cf. Jer. 5:22). God is holy and righteous, so that he is never the author or approver of sin—nor of suffering, which is the fruit of sin. Nevertheless, God is still sovereign over sin and suffering in the sense that he limits it, orders it, and redeems it for his holy purposes and for our good.

We might helpfully define suffering as the gap between promise and reality.[1] To the degree that things are not as they should be, then we are experiencing suffering. Therefore, as Abraham and Sarai (here renamed “Sarah”; Gen. 17:15) have awaited the promised offspring, their waiting has been suffering. We have seen them manage this suffering in different ways at different times: faithful obedience, cynical scheming, and lamenting prayer. By this point, both Abraham and Sarah are entirely beyond the age of child-bearing, humanly speaking. So, as God declares that he will now fulfill his promises, he stretches the faith of this couple beyond what they can think or imagine. This means more than that they find it difficult to get their minds around everything. Beyond that, their doubts represent a threat to the fulfillment of God’s mission that he seeks to accomplish in and through them. Still, the surprising point of Genesis 17:15–18:15 isn’t that Abraham and Sarah struggle to believe God’s word. Rather, the surprising part of this narrative is how God leads them to believe: God eats and drinks with us to overcome the limitations of our faith.

[1] This definition comes from the title of Iain M. Duguid’s book: Living in the Gap Between Promise and Reality: The Gospel According to Abraham (Phillipsburg, NJ: P&R Publishing, 1999).