10 Then one of them said, "I will return to you about this time next year, and your wife, Sarah, will have a son!" Sarah was listening to this conversation from the tent. 11 Abraham and Sarah were both very old by this time, and Sarah was long past the age of having children. 12 So she laughed silently to herself and said, "How could a worn-out woman like me enjoy such pleasure, especially when my master-my husband-is also so old?" 13 Then the Lord said to Abraham, "Why did Sarah laugh? Why did she say, 'Can an old woman like me have a baby?' 14 Is anything too hard for the Lord ? I will return about this time next year, and Sarah will have a son." 15 Sarah was afraid, so she denied it, saying, "I didn't laugh." But the Lord said, "No, you did laugh."

Matthew Henry's Commentary on Genesis 18:10-15

Commentary on Genesis 18:9-15

(Read Genesis 18:9-15)

Where is Sarah thy wife? was asked. Note the answer, In the tent. Just at hand, in her proper place, occupied in her household concerns. There is nothing got by gadding. Those are most likely to receive comfort from God and his promises, who are in their proper place, and in the way of their duty, 17; but He who searches the heart, saw that the one sprung from unbelief, and the other from faith. She denied that she had laughed. One sin commonly brings in another, and it is not likely we shall strictly keep to truth, when we question the Divine truth. But whom the Lord loves he will rebuke, convict, silence, and bring to repentance, and if they sin before him.