Genesis 17:18 And Abraham said to God, “Oh, that Ishmael might live before You!”
This statement to God is all to common among His people. The jest is this, Lord bless my flesh, carnal ideas, my logic. Gods not interested. He wants us to continue to trust, continue to seek, continue to knock. Abraham, at this point has all but given up yet the LORD keeps pouring out the strength to go on. The Seed of promise will only come thru promise and that of God. Gods answer: 21“But My covenant I will establish with Isaac, whom Sarah shall bear to you at this set time next year.”
There is no plan "B". This time next year, Isaac will be here meaning Sarah wasnt pregnant as of yet.