וַתְּכַחֵ֨שׁ שָׂרָ֧ה ׀ לֵאמֹ֛ר לֹ֥א צָחַ֖קְתִּי כִּ֣י ׀ יָרֵ֑אָה וַיֹּ֥אמֶר ׀ לֹ֖א כִּ֥י צָחָֽקְתְּ׃
Then Sarah denied, saying: ‘I laughed not’; for she was afraid. And He said: ‘Nay; but thou didst laugh.’
Read halakhic rulings (Jewish law) on Genesis 18:15: and classical halakhic sources.