“Now Sarai, Abram’s wife, had borne him no children” (16:1). And, so, rather than trusting God, Abram and Sarai concocted their own plans. We do not want to implicate Ishmael in this faithless scheme; after all, he had nothing to do with it even though his life was anything but a model of righteousness: “He shall be a wild donkey of a man, his hand against everyone and everyone’s hand against him, and he shall dwell over against all his kinsmen” (16:12).
This is Abram’s and Sarai’s doing. And even after God reaffirmed his promise to Abram, the man doubted and would have Ishmael to be counted as the son: “Oh that Ishmael might live before you!” (17:18) But God said, “No, but Sarah your wife shall bear you a son, and you shall call his name Isaac. I will establish my covenant with him” (17:19). God had promised and, whatever Abraham and Sarah might intend, God will do what he promised. As with this elderly couple, we have our plans but God has his! Can’t help but remember Proverbs 16:9: “The heart of man plans his way, but the Lord establishes his steps.” And what about: “’For my thoughts are not your thoughts, neither are your ways my ways,’ declares the Lord. ‘For as the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts’” (Isaiah 55:8-9). Oh, for hearts to trust God in all things!
The Lord our God in mercy spoke:
“A God to you I’ll be;
I’ll bless your numerous race, and they
shall be a seed to me.”
How faithful are the ways of God;
his love endures the same.
He keeps the promise of his grace,
preserves his children’s name. –Isaac Watts (1707)