Rabbi Chanina said: As a reward for the modesty that was in Rachel, that she handed over the signs to her sister, she merited that Saul came forth from her. And as a reward for the modesty that was in Saul, as it is written, "but about the matter of the kingship he did not tell him" (1 Samuel 10:16), he merited that Esther came forth from him, as it is written, "Esther did not reveal her kindred" (Esther 2:20).
Rachel's Modesty Rewarded Through Saul and Esther
Yalkut Shimoni on Torah 125:2
אָמַר רַבִּי חֲנִינָא, בִּשְׂכַר צְנִיעוּת שֶׁהָיְתָה בָּהּ בְּרָחֵל שֶׁמָּסְרָה לָהּ סִימָנִין לַאֲחוֹתָהּ, זָכְתָה וְיָצָא מִמֶּנָּה שָׁאוּל וּבִשְׂכָר צְנִיעוּת דַּהֲוָה בְּשָׁאוּל, דִּכְתִיב (שמואל א י, טז) "וְעַל דְּבַר הַמְּלוּכָה לֹא הִגִּיד לוֹ", זָכָה וְיָצְאָה מִמֶּנּוּ אֶסְתֵּר, דִּכְתִיב (אסתר ב, כ) "אֵין אֶסְתֵּר מַגֶּדֶת מוֹלַדְתָּהּ".