Galatians 4:23
But, indeed, he out of the slave-woman has been born according to flesh, and he out of the free woman through the promise;
Hebrews 11:11
By faith also Sarah herself received strength to conceive seed and was delivered of a child when she was past age, because she judged Him who had promised to be faithful.
Genesis 18:10-14
And He said, I will certainly return to you according to the time of life, and lo, Sarah your wife shall have a son. And Sarah heard in the tent door which was behind Him.
Genesis 21:1-2
And Jehovah visited Sarah as He had said. And Jehovah did to Sarah as He had spoken.
Romans 9:7-8
nor because they are the seed of Abraham are they all children. But, "In Isaac shall your Seed be called."
Genesis 17:15-19
And God said to Abraham, As for Sarai your wife, you shall not call her name Sarai, but her name shall be Sarah.
Romans 4:18-21
For he who beyond hope believed on hope for him to become the father of many nations (according to that which was spoken, "So your seed shall be").
Romans 10:8
But what does it say? "The Word is near you, even in your mouth and in your heart"; that is, the Word of Faith which we proclaim;
Galatians 4:28-29
But brothers, we, like Isaac, are children of promise.