הַפֹּרְטִ֖ים עַל־פִּ֣י הַנָּ֑בֶל כְּדָוִ֕יד חָשְׁב֥וּ לָהֶ֖ם כְּלֵי־שִֽׁיר׃
비파에 맞추어 헛된 노래를 지절거리며 다윗처럼 자기를 위하여 악기를 제조하며
Ibn Ezra
fallen grapes This term is known from tradition [Pe’a 7:3]. It is related to “pluck the strings of the lute” [Amos 6:5].
Rashi
backsliding children (Envasec in O.F.) That you perverted your way because of much good, that you enjoyed tranquility and pleasure, as Scripture states: They hum snatches of song to the tune of the lute (Amos 6:5), those who drink from bowls of wine (v. 6).