Psalm 98 has been called an enthronement hymn.
It was probably sung at the Festival of Trumpets to celebrate God's kingship over Israel.

As the ultimate King, the Lord saved the Israelites from slavery and from their surrounding enemies.
He did marvelous things and made his salvation known to his people.

Yet this psalm also contains universal themes of the prophet Isaiah..
that God would not only save Israel, but also the entire world.