Read Genesis 21:8-13
8 When Isaac grew up and was about to be weaned, Abraham prepared a huge feast to celebrate the occasion. 9 But Sarah saw Ishmael—the son of Abraham and her Egyptian servant Hagar—making fun of her son, Isaac. 10 So she turned to Abraham and demanded, “Get rid of that slave woman and her son. He is not going to share the inheritance with my son, Isaac. I won’t have it!”
11 This upset Abraham very much because Ishmael was his son. 12 But God told Abraham, “Do not be upset over the boy and your servant. Do whatever Sarah tells you, for Isaac is the son through whom your descendants will be counted. 13 But I will also make a nation of the descendants of Hagar’s son because he is your son, too.” (NLT)
Life can get very messy. We quite often mess things up, and our consolation is that God somehow manages to fulfil his good purposes despite our meddling. Our passage today is a good reminder. God had promised Abraham and Sarah a child who would in turn father a great nation. But time dragged on and this couple took things into their own hands so that Abraham had a son by a maid, Hagar.
Then when Sarah had her own son, Isaac, tensions arose in the household. Sarah wanted Hagar and her son, Ishmael, sent away. God intervened to sort things out. Hagar and Ishmael were to go off and yet Ishmael would not be forgotten. Though we read later there were desolate times for that mother and son. Isaac would be the one through whom God would raise a great nation. Though Isaac proved to be no pillar of integrity.
So it is that God works out his purposes in spite of our impatience and egocentricity and impulsiveness. We can’t see this as a sentimental, glib excuse for our wrongdoing. When we mess things up, people suffer: just ask Hagar about that.
But God doesn’t sit back wringing his hands or give up on us. He weaves his good purposes and actions into the not-so-good purposes and actions of his human creation. We mess, he mends.