Proverbs 20:9 Midrash

מִֽי־יֹ֭אמַר זִכִּ֣יתִי לִבִּ֑י טָ֝הַ֗רְתִּי מֵחַטָּאתִֽי׃

Who can say: ‘I have made my heart clean, I am pure from my sin’?

Read midrashic interpretation of Proverbs 20:9: and classical rabbinic exegesis.