The Son of God Goes Forth to War (1812) is a hymn, by Reginald Heber, set to the Irish tune The Moreen / The Minstrel Boy, and appears, with reworked lyrics, in the novella The Man Who Would Be King (1888), by Rudyard Kipling and in the film The Man Who Would Be King (1975), directed by John Huston.
References
The Son of God Goes Forth to War Wikipedia(Text) CC BY-SA