God hath made me to laugh - Sarah alludes here to the circumstance mentioned Genesis 18:12; and as she seems to use the word to laugh in this place, not in the sense of being incredulous but to express such pleasure or happiness as almost suspends the reasoning faculty for a time, it justifies the observation on the above-named verse. See a similar case in Luke 24:41, where the disciples were so overcome with the good news of our Lord's resurrection, that it is said, They believed not for joy.

And Sarah said, God hath made me to laugh,.... This she said on occasion of the name of her son Isaac, which name her husband had given him by divine direction, and to which she assented. This doubtless brought to her mind her former laughing, when she first heard that she should have a son, which was in a way of diffidence and distrust; but now God having given her a son, laid a foundation for laughter of another kind, for real, solid, joy and thankfulness:
so that all that hear will laugh with me; not laugh at her, and deride her, as Piscator interprets it; but congratulate her, and rejoice with her on this occasion, as on a like one the neighbours of Elisabeth did with her, Luke 1:58.

And Sarah said, God has made me to laugh - He hath given me both cause to rejoice, and a heart to rejoice. And it adds to the comfort of any mercy to have our friends rejoice with us in it, See Luke 1:58. They that hear will laugh with me - Others will rejoice in this instance of God's power and goodness, and be encouraged to trust in him.