The Spiritual Warfare by Arlen L Chitwood and published by Classics.
Christians are presently engaged in a battle against powerful angelic rulers in the spirit world. These angels, ruling in the kingdom of Satan, are striving for the souls of men; and the outcome of this conflict, like any conflict, is determined by proper or improper preparation as one engages the enemy. A properly prepared Christian can enter the conflict and consistently win battle after battle, but an improperly prepared Christian entering the conflict can only experience defeat time after time.
Victory is achieved through engaging the enemy within the framework of the Lord's instructions in Ephesians 6:10ff. A Christian though who engages the enemy after any other fashion is entering the conflict apart from the Lord's instructions, leaving himself in a very vulnerable position, one in which the enemy can consistently achieve victory. Thus, in this respect, victory on the one hand or defeat on the other is determined by the Christian’s preparation for the conflict at hand. A Christian can either heed the Lord's instructions or he can ignore the Lord's instructions. There is no middle ground (Matthew 12:30; Luke 11:23). The former will produce readiness for battle and result in victory, but the latter will leave the Christian very vulnerable to attack and can only result in defeat.