Homilies on the Epistle to the Hebrews

^5. “By faith also Sarah herself,” he says. Here he began [speaking] in a way to put them to shame, in case, that is, they should show themselves more faint-hearted than a woman. But possibly some one might say, How “by faith,” when she laughed? Nay, while her laughter indeed was from unbelief, her fear [was] from Faith, for to say, “I laughed not”, arose from Faith. From this then it appears that when unbelief had been cleared out, Faith came in its place.

“By faith also Sarah received strength to conceive seed even when she was past age.” What is, “to conceive seed”? She who was become dead, who was barren, received power for the retaining of seed, for conception. For her imperfection was two-fold; first from her time of life for she was really old; secondly from nature, for she was barren.