Psalms 66:4

All the earth shall worship thee
The Messiah, who is equal with God; the Creator of men; the Redeemer of his people; the Head of the church, and King of saints; their Lord, and therefore to be worshipped; with internal worship, in the exercise of faith, hope, and love; and with external worship, in the word and ordinances, by prayer and praise, public and private. This universal worship, that will be yielded him, will be in the latter day; which shows that this psalm respects those times, when Christ shall be King over all the earth, and his name, worship, and religion, one, ( Zechariah 14:9 Zechariah 14:16 ) ( Revelation 15:4 ) ;

and shall sing unto thee;
the song of Moses and the Lamb, the Lamb's new song, the song of redeeming grace; which none but the redeemed ever can sing aright, ( Revelation 14:3 ) ( 15:3 ) ;

they shall sing [to] thy name;
or, "they shall", or "let them sing thy name" ^F24; thou shall be the subject of their song; thy person, offices, kingdom, grace, and glory: or they shall sing to the honour of thy name, as in ( Psalms 66:2 ) .

Selah; on this word, (See Gill on Psalms 3:2).