This beloved hymn was written by Sigismund von Birken(1626-1681), who was born eight years into The Thirty Year’s War. It encourages us to live daily as baptized children of God by following Jesus and resisting the temptations of this world. The first English translation we have came from John Adam Rimbach (1871-1941), a Lutheran pastor who heard it in German at a district convention in 1900 and wanted to teach it in English to his congregation.
For more hymns and hymn stories see these posts:
The Battle Hymn of the Reformation