Jonah 3:4 Midrash

וַיָּ֤חֶל יוֹנָה֙ לָב֣וֹא בָעִ֔יר מַהֲלַ֖ךְ י֣וֹם אֶחָ֑ד וַיִּקְרָא֙ וַיֹּאמַ֔ר ע֚וֹד אַרְבָּעִ֣ים י֔וֹם וְנִֽינְוֵ֖ה נֶהְפָּֽכֶת׃

And Jonah began to enter into the city a day’s journey, and he proclaimed, and said: ‘Yet forty days, and Nineveh shall be overthrown.’

Read midrashic interpretation of Jonah 3:4: and classical rabbinic exegesis.