When God told Abraham that he was to have a son the following year, bible recorded it that Sarah laughed in her heart
12 Sarah laughed to herself, saying, “After I have become old, shall I have pleasure, my lord being old also?”
13 And the LORD said to Abraham, “Why did Sarah laugh, saying, ‘Shall I indeed bear a child, when I am so old?’
14 “Is anything too difficult for the LORD? At the appointed time I will return to you, at this time next year, and Sarah will have a son.”
15 Sarah denied it however, saying, “I did not laugh”; for she was afraid. And He said, “No, but you did laugh.”
I can see here that Sarah committed two [great] sins. 1) She mocked God 2) She called God a liar by denying she laughed.
My question is why God chose to overlook her sins and did not punish her for that?