While the author, a Christian salesman, aims Jungle Warfare at other Christians in sales, any churchperson can benefit. Believers must live their lives as part of the great struggle between good and evil which Christ came to fight and win. We are on the winning side, the reader is reminded, but the work is strenuous nonetheless. The author characterizes Christian living as a struggle; I don't become a Christian to feel warm and fuzzy but to engage in daily spiritual warfare.
We have to keep our wits about us and be prepared for the next challenge. The world flings all sorts of evil things at us, and, worst of all, our own pride brings us to sin.
The author recaptures well the militaristic side of Christian spirituality, which was developed by the earliest Christians, including the apostle Paul. He notes the importance of developing a fear of God. This understanding of God goes hand-in-hand with a sense of our own sinfulness. Fear of God and human sinfulness hold each other up as doctrines. We fear God because we know how sinful we are.
From this comes the call to total dependence on the Lord, the heart of the militia Christi. Christ is our commander and we are lost without Him. The Bible gives us a clear command code to follow.