Albert Barnes Commentary Psalms 66:4

"All the earth shall worship thee, And shall sing unto thee; They shall sing to thy name. Selah" — Psalms 66:4 (ASV)

All the earth shall worship thee - That is, all the inhabitants of the world will bow down before you, or render you homage. The time will come when your right to reign will be universally acknowledged, or when you will everywhere be adored as the true God. This is in accordance with all the statements in the Bible. See the notes at Psalms 22:27; Compare the notes at Isaiah 45:23; notes at Romans 14:11.

And shall sing unto thee - Shall celebrate your praises. To thy name. To you.