The Great Divorce.
My favorite quotes from the book:
"Having allowed oneself to drift, unresisting, unpraying, accepting every half-conscious solicitation from out desires, we reach a point where we no longer believe in Faith. Just in the same way, a jealous man, drifting and unresisting, reaches a point at which he believes the lies about his best friend: a drunkard reaches a point at which (for the moment) he actually believe that another glass will do him no harm. The beliefs are sincere in the sense that they do occur as psychological events in the man's mind. If that is what you mean by sincerity they are sincere, and so were ours. But errors which are sincere in that sense are not innocent."
Spirit: "It's only the little germ of a desire for God that we need to start the process."
Pam: "Oh, you mean religion and that sort of thing? This is hardly the moment... and from you, of all people. Well, never mind. I'll do whatever's necessary. What do you want me to do? Come on. The sooner I begin [the process to travel across heaven], the sooner they'll let me see my boy. I'm quite ready."
Spirit: "But Pam, do think! Don't you see you are not beginning at all as long as you are in that state of mind? You're treating God only as a means to Michael. But the whole thickening process consists in learning to want God for His own sake."
"Human being can't make one another really happy for long...He wanted your merely instinctive love for your child to turn into something better. He wanted you to love Michael as He understands love. You cannot love a fellow-creature fully till you love God. Sometimes this conversion can be done while the instinctive love is still gratified. But there still was, it seems, no chance of that in your case. The instinct was uncontrolled and the fierce and monomaniac. The only remedy was to take away the object. In was a case for surgery. When that first kind of love was thwarted, then there was a chance that in the loneliness, in the silence, something else might begin to grow."
Pam: "What right have you to say things about Mother-love? It is the highest and holiset feeling in human nature."
Spirit: " No natural feelings are high and low, holy or unholy, in themselves. They are all holy when God's hand is on the rein. They all go bad when they set up on their own and make themselves into false gods."
"But someone must say in general what's been unsaid among you this many a year: that love, as mortals understand the word, isn't enough. Every natural love will rise again and live forever in this country: but none will rise again until it has been buried."
"There is but one good; that is God. Everything else is good when it looks to Him and bad when it turns from Him. And the higher and mightier it is in the natural order, the more demonic it will be if it rebels. It's not out of bad mice or bad fleas you make demons, but out of bad archangels. The fase religion of lust is baser than the false religion of mother-love or patriotism or art: lust is less likely to be made into a religion."
"Every beast and bird that came near had [the Godly woman] had its place in her love. In her they became themselves. And now the abundance of life she has in Christ from the Father flows into them....It is like when you throw a stone into a pond, and the concentric waves spread out further and further. Who knows where it will end? Redeemed humanity is still young, it has hardly come to its full strength. But already there is joy enough in the little finger of a great saint such a yonder lady to waken all the dead things of the universe into life."
-C.S. Lewis