Genesis 21:2

“For Sarah conceived, etc.] This explains what is meant by the Lord’s visiting her, and doing to her according to his word, (see <581111> Hebrews 11:11); and bare Abraham a son in his old age; which circumstance is remarked, that the favour might appear the greater, and the more wonderful; or, “unto”, or “for his old age” f1210, for the comfort of him in his old age, who having lived so many years under the promise of a son, and in the expectation of one, even of the promised seed, from whom the Messiah should spring, now has one, than which nothing could yield him greater consolation: at the set time of which God had spoken to him, (<011721>Genesis 17:21 18:1014); God was not only faithful…”