[2][3] Wesley initially wrote the hymn as a poem titled "The Whole Armour of God, Ephesians VI" in 1747 and was used to defend against criticism of Methodism within Great Britain.

As a result, this hymn was written and also became known as "The Christian's bugle blast" because of the military references and the apparent call to arms when it was set to music.

This is speculated to be Wesley making reference to John Milton's poem, Paradise Lost where it says "Satan, with vast and haughty strides advanced, Came towering, armed in adamant and gold."

[1] Wesley wrote a unique piece of music entitled "Soldiers of Christ" for the hymn to be set to.

However, in the United States the main alternative piece of music that is used for the hymn is "Diademata" by George Job Elvey.