Why did God react to Abraham's laughter and Sarah's laughter concerning the promised son so differently?

[tonychanyt]

Genesis 17:

15 God also said to Abraham, “As for Sarai your wife, you are no longer to call her Sarai; her name will be Sarah. 16I will bless her and will surely give you a son by her. I will bless her so that she will be the mother of nations; kings of peoples will come from her.”
17 Abraham fell facedown; he laughed

Abraham laughed at God's promise to get Sarai pregnant with a son but he fell facedown, a posture of reverence towards God. His laughter was a human reaction to the seemingly impossible promise. His laughter could be more from joy/amazement. In any case, he laughed while in this posture of submission.

and said to himself, “Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?” 18 And Abraham said to God, “If only Ishmael might live under your blessing!”
19 Then God said, “Yes, but your wife Sarah will bear you a son, and you will call him Isaac.

Graciously, God reassured Abraham that Sarah would get pregnant. God didn't rebuke him.

A chapter later, three men visited Abraham in Genesis 18:

9“Where is your wife Sarah?” they asked him.
“There, in the tent,” he said.
10Then one of them said, “I will surely return to you about this time next year, and Sarah your wife will have a son.”
Now Sarah was listening at the entrance to the tent, which was behind him. 11 Abraham and Sarah were already very old, and Sarah was past the age of childbearing. 12 So Sarah laughed to herself as she thought, “After I am worn out and my lord is old, will I now have this pleasure?”

Like Abraham, Sarah laughed at the promise. Unlike Abraham, it wasn't accompanied with a reverence. On the contrary, she questioned God's promise. Her laughter was tinged with doubt/skepticism

13 Then the Lord said to Abraham, “Why did Sarah laugh and say, ‘Will I really have a child, now that I am old?’ 14 Is anything too hard for the Lord? I will return to you at the appointed time next year, and Sarah will have a son.”

This time, God rebuked Sarah for laughing.

15 Sarah was afraid, so she lied and said, “I did not laugh.”

She exhibited fear rather than reverence.

But he said, “Yes, you did laugh.”

When confronted, Sarah responded with denial.

Why did God react to these two instances of laughter so differently?

Both laughters stemmed from the seeming impossibility of having a child at their advanced ages. The different reactions had to do with their heart attitudes at the moment. God saw their hearts. Abraham laughed but he showed respect for God's word. Sarah laughed out of skepticism and denial.

Ironically, the name Isaac (meaning "he laughs"). I find that funny