וַיָּבֹ֨א יָרָבְעָ֧ם וְכָל־הָעָ֛ם אֶל־רְחַבְעָ֖ם בַּיּ֣וֹם הַשְּׁלִשִׁ֑י כַּאֲשֶׁ֨ר דִּבֶּ֤ר הַמֶּ֙לֶךְ֙ לֵאמֹ֔ר שׁ֥וּבוּ אֵלַ֖י בַּיּ֥וֹם הַשְּׁלִשִֽׁי׃
So Jeroboam and all the people came to Rehoboam the third day, as the king bade, saying: ‘Come to me again the third day.’
Read midrashic interpretation of II Chronicles 10:12: and classical rabbinic exegesis.