The Brooklyn Tabernacle Choir sang "The Battle Hymn of the Republic," a deeply religious and specifically Christian song. See below, esp at 2:39:
In the beauty of the lilies Christ was born across the sea,
With a glory in His bosom that transfigures you and me:
As He died to make men holy, let us die to make men free;
While God is marching on.
Glory! Glory! Hallelujah! Glory! Glory! Hallelujah!
Glory! Glory! Hallelujah! While God is marching on.