ויבו [וַיָּב֨וֹא] יָרָבְעָ֧ם וְכָל־הָעָ֛ם אֶל־רְחַבְעָ֖ם בַּיּ֣וֹם הַשְּׁלִישִׁ֑י כַּאֲשֶׁ֨ר דִּבֶּ֤ר הַמֶּ֙לֶךְ֙ לֵאמֹ֔ר שׁ֥וּבוּ אֵלַ֖י בַּיּ֥וֹם הַשְּׁלִישִֽׁי׃
Rashi on I Kings
My little finger is thicker. My little finger.1the beginning of his reign, Rechovom was 41 years old [See below 14:21], but Shlomo was only 12 years old when he became king [See above 3:7 and Rashi there].—Ralbag