In many churches Christianity has been watered down until the solution is so weak that if it were poison it would not hurt anyone, and if it were medicine it would not cure anyone!
I Talk Back to the Devil: Essays in Spiritual Perfection (1990).
It is doubtful whether God can bless a man greatly until He has hurt him deeply.
Glorify his name!, The Root of the Righteous, Ch. 39.
God wants us to worship Him. He doesn't need us, for He couldn't be a self-sufficient God and need anything or anybody, but He wants us. When Adam sinned it was not he who cried, 'God, where art Thou?' It was God who cried, 'Adam, where art thou?'
Worship: The Missing Jewel as quoted in Vernon K. McLellan (2000), Twentieth century thoughts that shaped the church p. 265.
Some of my friends good-humoredly – and some a little bit severely – have called me a 'mystic.' Well I'd like to say this about any w:mysticism I may suppose to have. If an arch-angel from heaven were to come, and were to start giving me, telling me, teaching me, and giving me instruction, I'd ask him for the text. I'd say, 'Where's it say that in the Bible? I want to know.' And I would insist that it was according to the scriptures, because I do not believe in any extra-scriptural teachings, nor any anti-scriptural teachings, or any sub-scriptural teachings. I think we ought to put the emphasis where God puts it, and continue to put it there, and to expound the scriptures, and stay by the scriptures. I wouldn't – no matter if I saw a light above the light of the sun, I'd keep my mouth shut about it 'til I'd checked with Daniel and Revelation and the rest of the scriptures to see if it had any basis in truth. And if it didn't, I'd think I'd just eaten something I shouldn't, and I wouldn't say anything about it. Because I don't believe in anything that is unscriptural or that is anti-scripture.
What Difference Does the Holy Spirit Make?
The true Christian experience must always include a genuine encounter with God. Without this, religion is but a shadow, a reflection of reality, a cheap copy of an original once enjoyed by someone else of whom we have heard. It cannot but be a major tragedy in the life of any man to live in a church from childhood to old age and know nothing more real than some synthetic god compounded of theology and logic, but having no eyes to see, no ears to hear, and no heart to love. 
The idea that this world is a playground instead of a battleground has now been accepted in practice by the vast majority of Christians. They are facing Christ and the world. ...The ‘worship’ growing out of such a view of life is as far off center as the view itself—a sort of sanctified nightclub without the champagne and the dressed-up drunks."
This World: Playground or Battleground? pp. 5-6
Modern civilization is so complex as to make the devotional life all but impossible. It wears us out by multiplying distractions and beats us down by destroying our solitude, where otherwise we might drink and renew our strength before going out to face the world again. … The thoughtful soul to solitude retires," said the poet of other and quieter times; but where is the solitude to which we can retire today? Science, which has provided men with certain material comforts, has robbed them of their souls by surrounding them with a world hostile to their existence.
Of God and Men, p. 125
We have measured ourselves by ourselves until the incentive to seek higher plateaus in the things of the Spirit is all but gone.
Of God and Men, p. 12
Truth is a glorious but hard mistress. She never consults, bargains or compromises.
Of God and Men, p. 39
Complacency is the deadly enemy of spiritual progress. The contented soul is the stagnant soul.
The Size of the Soul, p. 22
I find that many men and women are troubled by the thought that they are too small and inconsequential in the scheme of things. But that is not our real trouble—we are actually too big and too complex, for God made us in His image and we are too big to be satisfied with what the world offers us! … Man is bored, because he is too big to be happy with that which sin is giving him. God has made him too great, his potential is too mighty.
Who Put Jesus on the Cross, p. 170
We have become so engrossed in the work of the Lord that we have forgotten the Lord of the work.
Many of us Christians have become extremely skillful in arranging our lives so as to admit the truth of Christianity without being embarrassed by its implications. We arrange things so that we can get on well enough without divine aid, while at the same time ostensibly seeking it.
In our constant struggle to believe we are likely to overlook the simple fact that a bit of healthy disbelief is sometimes as needful as faith to the welfare of our souls. I would go further and say that we would do well to cultivate a reverent skepticism. It will keep us out of a thousand bogs and quagmires where others who lack it sometimes find themselves. It is no sin to doubt some things, but it may be fatal to believe everything. Faith is at the root of all true worship, and without faith it is impossible to please God. Through unbelief Israel failed to inherit the promises. “By grace are ye saved through faith.” “The just shall live by faith.” Such verses as these come trooping to our memories, and we wince just a little at the suggestion that unbelief may also be a good and useful thing. … Faith never means gullibility. The man who believes everything is as far from God as the man who refuses to believe anything. Faith engages the person and promises of God and rests upon them with perfect assurance. Whatever has behind it the character and word of the living God is accepted by faith as the last and final truth from which there must never be any appeal. Faith never asks questions when it has been established that God has spoken. 'Yea, let God be true, but every man a liar' (Rom. 3:4). Thus faith honors God by counting Him righteous and accepts His testimony against the very evidence of its own senses. That is faith, and of such we can never have too much. Credulity, on the other hand, never honors God, for it shows as great a readiness to believe anybody as to believe God Himself. The credulous person will accept anything as long as it is unusual, and the more unusual it is the more ardently he will believe. Any testimony will be swallowed with a straight face if it only has about it some element of the eerie, the preternatural, the unearthly.
Whatever a man wants badly and persistently enough will determine the man's character.
Any belief that does not command the one who holds it is not a real belief; it is a pseudo belief only.
One hundred religious persons knit into a unity by careful organization do not constitute a church any more than eleven dead men make a football team. The first requisite is life, always.
The truly spiritual man is indeed something of an oddity. He lives not for himself but to promote the interests of Another. He seeks to persuade people to give all to his Lord and asks no portion or share for himself. He delights not to be honored but to see his Saviour glorified in the eyes of men. His joy is to see his Lord promoted and himself neglected. He finds few who care to talk about that which is the supreme object of his interest, so he is often silent and preoccupied in the midst of noisy religious shoptalk. For this he earns the reputation of being dull and overserious, so he is avoided and the gulf between him and society widens. He searches for friends upon whose garments he can detect the smell of myrrh and aloes and cassia out of the ivory palaces, and finding few or none he, like Mary of old, keeps these things in his heart.
To be right with God has often meant to be in trouble with men.
God … must always be sought for Himself, never as a means toward something else. Whoever seeks God as a means toward desired ends will not find God. The mighty God, the maker of heaven and earth, will not be one of many treasures, not even the chief of all treasures. He will be all in all or He will be nothing. God will not be used.