21:6כ״א:ו׳
1 א

יצחק לי. יִשְׂמַח עָלַי. וּמִ"אַ הַרְבֵּה עֲקָרוֹת נִפְקְדוּ עִמָּהּ, הַרְבֵּה חוֹלִים נִתְרַפְּאוּ בוֹ בַיּוֹם, הַרְבֵּה תְפִלּוֹת נַעֲנוּ עִמָּהּ, וְרֹב שְׂחוֹק הָיָה בָעוֹלָם:

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.