God is in the trombone
The trombone is said to have been invented in the middle of the 15th century, at which time it was closely associated with Christian church music. The trombone began to be used for other kinds of music during the 18th century, but for this reason it was often used to symbolize God or supernatural phenomena.
The trombone is famous for the impressive solo at the end of Mozart's "Requiem," in which the instrument announces the Last Judgment. Another example is the opera "Don Giovanni," also by Mozart. During the scene where Don Giovanni is sent to Hell without repenting for his life of debauchery, the trombone is used to symbolize a supernatural force that reaches beyond human intellect. Mozart is said to have picked up on this from Gluck and Salieri, two older composers.
Two extremely interesting examples of how the trombone is used can be found in the final two movements of Beethoven's "Pastoral Symphony." During the fourth movement (which depicts a thunderstorm and lightning) the instrument is used to represent the powerlessness of man in the face of nature. During the fifth movement, the trombone symbolizes mankind's gratitude toward God.