Ephesians 6:13 exhorts us to “take up the full armor of God, so that you will be able to resist in the evil day, and having done everything, to stand firm.” But suppose that armor, through negligence, begins to rust? William Gurnall directs us, then, to “apply thyself to the use of those means which God hath appointed for the strengthening [of] grace.”

   1. I shall sent thee to the Word of God; be more frequently conversant with it. David tells us where he renewed his spiritual life, and got his soul so oft into a heavenly heat, when grace in him began to chill. The Word, he tells us, quickened him. . . . Now the Word brings the Christian graces and their object together. Here love may delight herself with the beholding Christ, who is set out to life there in all his love and loveliness. Here the Christian may see his sins in a glass that will not flatter him; and can there any godly sorrow be in the heart, any hatred of sin, and not come forth, while the man is reading what they cost Christ for him?
   2. From the word go to meditation. This is as bellows to the fires. That grace which lies choked and eaten up for want of exercise, will by this be cleared and break forth. While thou art musing this fire will burn, and thy heart grow hot within thee, according to the nature of the subject thy thoughts dwell upon. Resolve, therefore, Christian, to inclose time from all worldly suitors, wherein thou mayest every day, if possible, at least take a view of the most remarkable occurrences that have passed between God and thee.
   (1.) Ask thy soul what takings it hath had that day, what mercies heaven hath sent into thee? and . . . stay till thy soul has made report of God’s gracious dealings with thee. . . . There is a great treasure of mercy always in the Christian's hands, and conscience is oft calling the Christian to take the account, and see what God has done for him; but seldom it is he can find time to tell his mercies over. And is it any wonder that such should go behind-hand in their spiritual estate, who take no more notice of what the gracious dealings of God are with them? How can he be thankful that seldom thinks what he receives? or patient when God afflicts, that wants one of the most powerful arguments to pacify a mutinous spirit in trouble, and that is taken from the abundant good we receive at the hands of the Lord as well as a little evil? how can such a soul’s love flame to God, that is kept at such a distance from the mercies of God, which are fuel to it? And the like might be said of all the other graces.
   (2.) Reflect upon thyself, and bestow a few serious thoughts upon thy own behaviour—what it hath been towards God and man all along the day. . . .
   3. From meditation go to prayer. Indeed, a soul in meditation is on his way to prayer; that duty leads the Christian to this, and this brings help to that. When the Christian has done his utmost by meditation to excite his graces, and chase his spirit into some divine heat, he knows all this is but to lay the wood in order. The fire must come from above to kindle, and this must be fetched by prayer. . . .
   4. To all the former, join fellowship and communion with the saints thou livest amongst. No wonder to hear a house is robbed that stands far from neighbours. He that walks in communion of saints travels in company, he dwells in a city where one house keeps up another . . . The devil knows what he does in hindering this great ordinance of communion of saints—in doing this he hinders the progress of grace, yea, brings that which Christians have into a declining, wasting state. The apostle couples those two duties close together, to ‘hold fast’ our ‘profession,’ and to ‘consider one another to provoke unto love and to good works,’ He. x. 23, 24.

—William Gurnall, The Christian in Complete Armour (Banner of Truth Trust, 2002), 1:239–241.