Yaratılış 21:6

יצחק לי means will rejoice on my account. The Midrashic statement is (Genesis Rabbah 53:8): Many barren women were remembered together with her, many sick were healed in that day, many prayers were answered with hers and there was great rejoicing in the world.

And Sara said, God has made laughter for me, so that all that hear will laugh with me.

וַתֹּ֣אמֶר שָׂרָ֔ה צְחֹ֕ק עָ֥שָׂה לִ֖י אֱלֹהִ֑ים כׇּל־הַשֹּׁמֵ֖עַ יִֽצְחַק־לִֽי׃