Gott mitt uns!
Yeah I had no idea what they meant either until I read this fantastic article over at Daylight Atheism. I suppose some of the better educated might recognize them.
Despite their origins in different languages and cultures, all four of these phrases express basically the same proposition: that God is on our side and will grant us victory over our enemies. Under all four of these mottoes, armies have marched to war, secure in their faith that the Almighty was championing their cause and would permit them to slay their foes with terrible slaughter.
Seriously go read the article, it's good, a little long but worth the time.