וּמָ֣צָא בָ֗הּ אִ֤ישׁ מִסְכֵּן֙ חָכָ֔ם וּמִלַּט־ה֥וּא אֶת־הָעִ֖יר בְּחָכְמָת֑וֹ וְאָדָם֙ לֹ֣א זָכַ֔ר אֶת־הָאִ֥ישׁ הַמִּסְכֵּ֖ן הַהּֽוּא׃
now there was found in it a man poor and wise, and he by his wisdom delivered the city; yet no man remembered that same poor man.
Read midrashic interpretation of Ecclesiastes 9:15: and classical rabbinic exegesis.