Be careful of every vain hope: it is in reality a temptation to despair. It may seem very real, very substantial. You may come to depend far too much on this apparent solidity of what you thik is soon to be yours. You may make you whole spiritual life, you very faith itself, depend on on this illusory promise. Then, when it dissolves into air, everything else dissolves along with it. Your whole spiritual life slips away between your fingers and you are left with nothing.
In reality, this could be a good thing, and we should be able to regard it as a good thing, if only we could fall back on the substantiality of pure and obscure faith, which cannot deceive us. But our faith is weak. Indeed, too often the weakest thing about our faith is the illusion that our faith is strong, when the “strength” we feel is only the intensity of emotion or sentiment, which have nothing to do with real faith.
–Thomas Merton, New Seeds of Contemplation