Albert Barnes Commentary Psalms 47:6

"Sing praise to God, sing praises: Sing praises unto our King, sing praises." — Psalms 47:6 (ASV)

Sing praises to God, sing praises - This commences the “second” part of the psalm. The “repetition” shows that the heart was full, or was overflowing with joy. It is a call on all to celebrate the praises of God, especially as he had enabled his people to triumph over their enemies.

Sing praises unto our King - To God, who has shown himself to be the King of his people—one who rules on their behalf, and who has intervened for their deliverance in danger.