Psalm 47:1-2 (KJV)
O clap your hands, all ye people; shout unto God with the voice of triumph.
2 For the Lord most high is terrible; he is a great King over all the earth.
The psalm, therefore, is a triumphal ode, and was probably composed to be sung on occasion of some military triumph - some solemn procession on a return from battle, with captive princes marching in the procession, and with a display of the “shields” and other implements of war taken from the foe. All this is celebrated as indicative of the interposing power of God in victory, and as evidence of his purpose to protect his chosen people in time of peril. The psalm may yet be used in a higher sense by the church at large, when all the foes of God on earth shall be subdued, and when his kingdom shall be in fact set up over all the world.