עִבְד֣וּ אֶת־יְהוָ֣ה בְּיִרְאָ֑ה וְ֝גִ֗ילוּ בִּרְעָדָֽה׃
여호와를 경외함으로 섬기고 떨며 즐거워할지어다
Rashi
and rejoice with quaking When the quaking, about which it is written (Isa. 33:14): “Trembling seized the flatterers,” comes, you will rejoice and be happy if you have served the Lord.
Radak
Serve the Lord: – Take pleasure in what He takes pleasure in, and serve Him
Ibn Ezra
Serve (עִבְדוּ - ivdu): [This command is] the opposite of their words [in verse 3], "Let us break (nenattekah) [their cords]." And the service of HaShem [should be] out of fear (le-yir'ah) of Him, and [so as] not to transgress His command (lit. His mouth).