An English hymn originally written as a processional by Baring- Gould was later adopted as a Christian hymn because of the reference to II Timothy 2:3 of being a soldier for Christ. Yes, it has accepted as a Christian Hymn.

Onward Christian Soldiers - ???? is rated/received certificates of:

UK:PG

A Mighty Fortress Is Our God

Eternal Father, Strong to Save (known as Naval hymn)

Onward Christian Soldiers.

Perhaps "Onward Christian Soldiers".

The cast of Onward Christian Soldiers - 1918 includes: Isobel Elsom as The Girl Minna Grey as The Sister Owen Nares as The Soldier Tom Reynolds as The Man