וַֽיְהִי֙ אַֽחֲרֵי־כֵ֔ן וַיַּ֥ךְ לֵב־דָּוִ֖ד אֹת֑וֹ עַ֚ל אֲשֶׁ֣ר כָּרַ֔ת אֶת־כָּנָ֖ף אֲשֶׁ֥ר לְשָׁאֽוּל׃ (ס)
And it came to pass afterward, that David’s heart smote him, because he had cut off Saul’s skirt.
Read midrashic interpretation of I Samuel 24:6: and classical rabbinic exegesis.