As a Marine officer, Dan McGuire learned the "operations order"- the standard five-part procedure that militaries use to conduct combat missions. Today he's a theologian and evangelist, and in Marching Orders he adapts the operations order to the mission of spiritual combat: the battle to save souls. Each of us is charged by our commander-in-chief Jesus Christ with the solemn mission to preach the gospel to the whole world (Matt. 28:16-20). This is...