Judges 5:3

3. Kings… princes The kings and princes of the Canaanites (and, indeed, of all the earth) are referred to, not the princes of Israel, for Israel, at this time, had no kings. The prophetess, having opened her song with an exclamation of blessing to Jehovah, now boldly calls on the heathen kings to listen to her strains of triumph, and from them take warning and instruction. Compare Psalms 2:10.

I… even I will sing That is, I, Deborah; comp. Judges 5:7. “O kings,” she says, in lofty defiance, “I, even I, a feeble woman, sing a song of triumph over you.”

Will sound the harp The original word rendered “sound the harp,” is the one used for singing with an instrument. She will not only sing, but play with a stringed instrument to the Lord.