Why is hope compared to a helmet? The helmet defends the head… from dint of bullet and sword… This hope defends the soul… whereby no dangerous or deadly impression can by Satan or sin be made on it.. As the helmet defends the soldier’s head from wounding, so his heart also from swooning. It makes him bold and fearless in battle.
A man cannot drown so long as his head is above water. Now it is the proper function of  hope to do this for the Christian in times of danger… Two things make the head hang down–fear and shame. Hope eases the Christian’s heart of both.. and so forbids him to give any sign of a desponding mind by a dejected countenance.
—William Gurnall “The Christian in complete Armour”

In considering the whole course of David’s life it seems to me that at his every step he showed me the way. This was for me a marvelous solace. For although with continual wars this holy king was troubled by the philistines and other foreign nations, his enemies, still more grievously was he stricken in the midst of his own people by the ill will of certain disloyal, vicious men. I can say similarly of myself: On all sides have I been assailed, scarcely even for a moment experiencing repose; always the brunt of some attack either from without or from within. Satan has often tried by his plots to overthrow the whole structure of this church.
—John Calvin “The Piety of John Calvin”

If the understanding be clear in its apprehension of truth, and the will sincere, vigorous, and fixed in its purposes for that which is holy and good, then he is a strong Christian… Satan comes as a serpent in the persons of false teachers, [or] as a lion in the persons of bloody persecutors… To defend us against this, we need to have truth girt about us, so that with a holy resolution we may maintain our profession in the face of death and danger.
—William Gurnall “The Christian in complete Armour”

The world is Satan’s bait. He seldom throws out a naked hook. Let murder, fraud, lying, or idolatory be presented in their undisguised turpitude, and only few people of good education and correct morals will be taken in by him. But he conceals the hook in a godly bait, and like a skillful angler, he knows how to use the temptation best suited to our palate… For one, he has a golden bait; for another, pleasure; for a third, worldly fame and honours.
And his line is thrown out everywhere–in our place of business, in our families, in our studies, at our tables and on our pillows.
—Arthur Jackson, “A Homiletic Encyclopedia” p. 4680

The Christian’s state in this life is one of combat… He needs his sword as much as his trowel… The Christian is assailed on every side by his enemy. How can it be otherwise, when the seeds of war are laid deep within the natures of both, and can never be rooted up until the devil cease to be a devil, sin to be sin, and saint to be saint?… Sin will lust against grace, and grace draw upon sin, whenever they meet.
William Gurnall “The Christian in Complete Armour”

The fourth piece in the Christian’s panoply… is the shield of faith. Justifying faith. A grace that makes  him the devils match… not a naked assent to the truths of the gospel [but] an act of the soul whereby it rests on Christ crucified for pardon and life, and that upon the warrant of [God's] promise.
Faith is… a shield intended for the defense of the whole body… Sometimes temptation is levelled at the head… against this truth and that, to make the Christian call them into question… blot out the Deity of Christ, with other mysterious truths of the Gospel… Now faith comes between the Christian and this arrow. It comes into the relief of the Christian’s weak understanding.
—William Gurnall “Christian in complete Armour.”

David’s condition was such, that deserving his people’s esteem, he was nontheless groundlessly hated by many (as he complained that “he had paid back what he had not taken away”). No small consolation for me it was— when assaulted by the unwarranted hatred of those who should have put their efforts into  helping me—To conform myself to such a great, excellent pattern.
And this very knowledge and experience was a great help to me in understanding the Psalms, to keep me from wandering, as it were, in a strange land. And actually, my readers, (I am sure) will recognize that when I recount the inner feelings both of David and of others, I am speaking of them as things, with which I am intimately acquainted.
—John Calvin, “The Piety of John Calvin” pp. 56

This then is our plea: Not to be vanquished, overwhelmed by temptations. But by the Lord’s power to stand unmoved against all hostile powers attacking us. This it is not to succumb to temptations. Our plea: received into His care and safekeeping, secure in His protection, grant us victoriously to endure, sin, death, the gates of hell, the devil’s whole kingdom. So it is to be “freed from the evil one.” Mark this clearly: Not in our power is it for us to engage in combat that great warrior the devil or bear alone the force of his onslaught. Otherwise, pointless it would be to ask God what already we have in ourselves. Those who, self-assured, ready themselves for combat, know not their ferocious, well-equipped adversary. As from the jaws of a  mad and raging lion, we seek now to be freed from his power. If the Lord did not snatch us from the midst of death, we would by his fangs and claws immediately be torn to pieces. Swallowed down his throat. Still we know if the Lord is with us, if He fights for us while we keep still, in His might we shall do mightily. Let others trust in their free choice, their own capacities–For us, enough it is to stand, be strong, in God’s power alone.
From “The Piety of John Calvin” pp. 141, Ford Lewis Battle ed.

The Christian’s state in this life is one of combat… He needs his sword as much as his trowel.. The Christian is assailed on every side by his enemy. How can it be otherwise? When the seeds of war are laid deep in the natures of both, and can never be rooted up till the devil cease to be a devil, sin to be sin, and saint to be a saint?… Sin will lust against grace, and grace draw upon sin whenever they meet.>–William Gurnall “Christian in complete Armour”

It is fit that professors of all sorts should be reminded of these things; for we may see not a few of them under visible decays, without any sincere endeavours after a recovery, who yet please themselves that the root of the matter is in them. It is so, if love of the world, conformity unto it, negligence in holy duties, and coldness in spiritual love, be an evidence of such decays. but let none deceive their own souls; wherever there is a saving principle of grace, it will be thriving and growing unto the end. And if it falls under obstructions, and thereby into decays for a season, it will give no rest or quietness unto the soul, wherein it is, but will labour continually for a recovery. Peace in a spiritually decaying condition is a soul ruining security; better be under terror on the account of surprisal into some sin, than be in peace under evident decays of spiritual life.
—John Owen

The way to prevail is to get the victory over the pride of our own nature, by taking shame to ourselves, in humble confession to God; to overcome the unbelief of our hearts, by yielding to the promise of pardon; to set ourselves against those sins which have prevailed over us, in confidence of Christ’s assistance. Then, prevailing over ourselves, we shall easily prevail over all our enemies.
—Richard Sibbes “The Bruised Reed.”

The sixth and last piece in the Christian’s panoply: the sword of the Spirit, which is the word of God…By the edge of this, his enemies fall and all his great exploits are done …A it defends the soldier, so it offends his enemy. By it he kills and mortifies his lusts within, and this makes his victory complete.
—William Gurnall “The Christian in Complete Armour