לַמְנַצֵּ֥חַ עַֽל־יְדוּת֗וּן מִזְמ֥וֹר לְדָוִֽד׃
Rashi on Psalms
on jeduthun The name of a musical instrument. The Midrash Aggadah, though, [explains it to mean]: concerning the ordinances (דתות) and laws that are decreed upon Israel by their enemies.