הַפֹּרְטִ֖ים עַל־פִּ֣י הַנָּ֑בֶל כְּדָוִ֕יד חָשְׁב֥וּ לָהֶ֖ם כְּלֵי־שִֽׁיר׃
Sila na umaawit nang paputol-putol sa saliw ng alpa, at inaakala nilang ang kanilang mga instrumento ng musika ay gaya ng kay David!
Rashi
Who sing according to the tone of the lute—Menahem (Machbereth Menahem p. 145) classifies it with (Lev. 19:10) “And the single grapes (וּפֶרֶט) of your vineyard,” and I approve of his view, for the one who sings with a musical instrument separates the speech individually, everything according to the tone of the instrument, whether to raise [the note] or to lower [it].
Rashi
they thought their musical instruments were like [those of] David—They thought their musical instruments were like the musical instruments of your servant David, which were meant for the sake of Heaven, but these were for enjoyment.