By faith Sarah, even though she was barren and beyond the proper age, was enabled to conceive a child, because she considered Him faithful who had promised.

Genesis 17:19
But God replied, "Your wife Sarah will indeed bear you a son, and you are to name him Isaac. I will establish My covenant with him as an everlasting covenant for his descendants after him.

Genesis 18:11
And Abraham and Sarah were already old and well along in years; Sarah had passed the age of childbearing.

Genesis 21:2
So Sarah conceived and bore a son to Abraham in his old age, at the very time God had promised.

Romans 9:8
So it is not the children of the flesh who are God's children, but it is the children of the promise who are regarded as offspring.

Galatians 4:23
His son by the slave woman was born according to the flesh, but his son by the free woman was born through the promise.

Hebrews 10:23
Let us hold resolutely to the hope we profess, for He who promised is faithful.

Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised.