וַיְהִ֣י ׀ בַּיּ֣וֹם הַשְּׁלִישִׁ֗י וַתִּלְבַּ֤שׁ אֶסְתֵּר֙ מַלְכ֔וּת וַֽתַּעֲמֹ֞ד בַּחֲצַ֤ר בֵּית־הַמֶּ֙לֶךְ֙ הַפְּנִימִ֔ית נֹ֖כַח בֵּ֣ית הַמֶּ֑לֶךְ וְ֠הַמֶּלֶךְ יוֹשֵׁ֞ב עַל־כִּסֵּ֤א מַלְכוּתוֹ֙ בְּבֵ֣ית הַמַּלְכ֔וּת נֹ֖כַח פֶּ֥תַח הַבָּֽיִת׃
Now it came to pass on the third day, that Esther put on her royal apparel, and stood in the inner court of the king’s house, over against the king’s house; and the king sat upon his royal throne in the royal house, over against the entrance of the house.
Rashi
And to his fasting: The third day of his fasting, as they began to fast on the fourteenth of Nissan. And that which Scripture stated about the previous day (Esther 5:1) - "On the third day, Esther put on royal apparel" - that was the third day from the sending of the runners.