Finally, my brethren, be strong in the Lord, and in the power of his might. Put on the whole armor of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. Wherefore take unto you the whole armor of God, that ye may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; And your feet shod with the preparation of the gospel of peace; Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. And take the helmet of salvation, and the sword of the Spirit, which is the word of God: Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints.

(Paul’s epistle to the Ephesians).

While staying at a castle in France, Erasmus shared time with a knight who was loosing or perhaps already lost his faith. At the behest of a concerned wife, the knight asked Erasmus to write him a guidebook for living an authentic Christian life. The result, which was envisioned as a ‘handy weapon’ for the Christian soldier, became one of the best known ‘self-help’ books of the age.

In this life it is necessary that we be on our guard. … Life here below is best described as being a type of continual warfare. Yet the great majority of mankind is often deceived, for the world, like some deceitful magician, captivates their minds with seductive blandishments, and as a result most individuals behave as if there had been a cessation of hostilities. They celebrate as if they were assured of victory when, as a matter of fact, genuine peace could never be further away. It is amazing to see in what false security these people live and in what a complacent manner they close their minds to reality. In the meantime the vices, our armored enemies, attack us unceasingly; we are entrapped by their espionage and assaulted by their endless deceptions. If you but look around, you will see that regardless of where you go they are observing you. They are prepared to attack us with a thousand stratagems… . Unless we ward them off with the impenetrable shield of faith, they will prove to wield weapons of certain death. …

Man is a very complex creature composed of several contending parts: a soul, which may be likened to a sort of divine will, and a body, comparable to a dumb beast. …In man, reason discharges the office of king…. Though our king, reason, may at times be oppressed, he cannot be corrupted without protesting…. This then is the only road to happiness: first, know yourself; do not allow yourself to be led by the passions, but submit all things to the judgement of reason. Be sane and let reason be wise, that is, let it gaze upon decent things.

[…]

But to place the whole of religion in external ceremonies is sublime stupidity…. Charity does not consist in many visits to churches, in many protestations before the statues of saints, in the lighting of candles, or in the repetition of a number of designated prayers. Of all these things  God has no need…. To observe these unimportant things is, of course, wholesome, but to make them the object of your devotions is extremely dangerous. He [St. Paul] is not opposed to good works (without them it would be impossible to be a good Christian), yet they do not  make the Christian….

I am not advocating that you neglect the mandates of the Church or that you despise honorable traditions and godly customs…. I am not condemning manual works, but I am trying to impress upon you that such works are of little value unless they are accompanied by internal piety.