וַיָּ֣קָם יוֹנָ֗ה וַיֵּ֛לֶךְ אֶל־נִֽינְוֶ֖ה כִּדְבַ֣ר יְהוָ֑ה וְנִֽינְוֵ֗ה הָיְתָ֤ה עִיר־גְּדוֹלָה֙ לֵֽאלֹהִ֔ים מַהֲלַ֖ךְ שְׁלֹ֥שֶׁת יָמִֽים׃
So Jonah arose, and went unto Nineveh, according to the word of the LORD. Now Nineveh was an exceeding great city, of three days’journey.
Read Jewish philosophy on Jonah 3:3: Rambam's Guide for the Perplexed, Saadia Gaon, and classical Jewish philosophical sources, free online.