Therefore (literally, and) Sarah laughed within herself—Abraham had laughed in joyful amazement, (Genesis 18:17) at the first mention of Sarah's son; Sarah laughs, if not in unbelief (Calvin, Keil, 'Speaker's Commentary,' Wordsworth), at least with a mingled feeling of doubt and delight (Lange, Murphy) at the announcement of her approaching maternity—saying, After I am waxed old shall I have pleasure, my lord being old also?
—literally, and my lord, i.e. my husband, is old. The reverential submission to Abraham which Sarah here displays is in the New Testament commended as a pattern to Christian wives (1 Peter 3:6).