God asked to deal with the enemies of Israelverses 1-2

 Let God arise - let HIS enemies be scattered

let them also that hate HIM flee before HIM

      as smoke is driven away - so drive them away

                  as wax melts before the fire

so let the wicked perish at the presence of God

Righteous need to shout for joy before Godverses 3-4

 BUT let the righteous be glad - let them rejoice before…