The hymn text is ancient, based on a poem written by Francis of Assisi in 1225. It was inspired by Psalm 148 which calls all creation to worship God. The psalm is longer but includes these verses:
Praise the Lord from the earth, you great sea creatures and all ocean depths,
lightning and hail, snow and clouds, stormy winds that do his bidding,
you mountains and all hills, fruit trees and all cedars, wild animals and all cattle,
small creatures and flying birds….
Let them praise the name of the Lord, for his name alone is exalted….