God also said to Abraham, “As for Sarai your wife, you are no longer to call her Sarai; her name will be Sarah. I will bless her and will surely give you a son by her. I will bless her so that she will be the mother of nations; kings of peoples will come from her.”

Abraham fell facedown; he laughed and said to himself, “Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?” And Abraham said to God, “If only Ishamel might live under your blessing!”

Then God said, “Yes, but your wife Sarah will bear you a son, and you will call him Isaac. I will establish my covenant with him as an everlasting covenant for his descendants after him.” – Genesis 17:15-19

God’s plan to redeem His creation was all set up. He had called and chosen Abram to be the father of the nation God will use to bless and save the whole world. Despite his old age, Abram was blessed with a son, Ishmael, who would inherit his family name and the promises God committed to them.

But Abraham’s wife Sarai was not the mother of Ishmael. Though she had been faithful to her husband and his calling, by this time it seems she will play only a secondary role in the covenant promises. God will come through for the covenant family. But, her frustration and heartbreak are real.

Now Abram is meeting with God again. The covenant promises of people, place and blessing are re-confirmed. He even receives a new name: Abraham, the father of many nations. But then, a twist. God has a new name for Sarai as well – a name that proclaims her a mother of nations. It is Sarah’s turn, in defiance of time and nature, to be given a son. And it is through this son that the covenant family will endure and grow.

This is utterly incredible. Abraham cannot help but laugh at the sheer wonder, almost absurdity of this promise he knows must be true. A laugh of unlooked-for joy, an admixture of euphoria bordering on disbelief. The same laughter bursts from Sarah when she later hears the news. The same laughter we imagine Mary must have enjoyed when she pondered her own child of promise.

No circumstance is too hard for God. Sarah had given up hope for herself, only for God to break through with an unexpected joy. Centuries later, the children of Israel groaned with the whole world for the promised Saviour to finally appear. He came not as a mighty prince but as a small, vulnerable child. He was born to a virgin in a feeding trough for animals. When He conquered, it was not as a warrior-king. It was a suffering servant raised to life when all hope had seemed lost.

The joy of Christmas is the joy of the unexpected. We don’t find it just in good times and good food. It is joyous because it is so utterly baffling. The answer to our rebellion and the curse of death is for the pure and holy Creator God to enter our world as a human child, as one of us.

Would you have seen that coming? How many times have we let go of joy in the face of frustration, only for God to deliver in the craziest of ways?

Lord, we remember with gratitude and gladness your covenant promises to Israel. We thank you that you have fulfilled those promises time and time again, even in ways we did not expect. Amen.

Take a moment to remember a time when God came through for you in an unexpected way. Describe that feeling of relief, amazement, or joy when you realised what He had done for you. Write that moment down somewhere you can return to it. Perhaps in a journal, or on a slip of paper to hang on the tree or stow in your stocking for Christmas Day.

Abraham and Sarah named their promised child Isaac, meaning “he laughs.” May the unexpected joy of the Lord overflow from our hearts this Advent. May it bring light and laughter to all those who have been in darkness.