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.
Ver. 11. Because she judged him, &c.] At first she laughed, through unbelief, at the unlikelihood; but afterward she bethought herself, and believed. This latter is recorded, the former pardoned. So Genesis 18:12, "Sarah laughed within herself, saying, After I have waxen old shall I have pleasure, my lord being old also?" Here was never a good word but one, viz. that she called her husband lord, and this is recorded to her eternal commendation,1 Peter 3:6. Isaac then was not a child of nature, but of the mere promise; so are all our graces. We bring forth good things, as Sarah's dead womb brought forth a child.