But the son of the slave was born according to the flesh, the son of the free woman through promise.
But what does it say? The word is near you, on your lips and in your heart (that is, the word of faith which we preach);
For it is written that Abraham had two sons, one by a slave and one by a free woman.
By faith Sarah herself received power to conceive, even when she was past the age, since she considered him faithful who had promised.