Chapter XVIII. Of the zeal with which we should seek the desert, and of the things in which we make progress there. Further , it is those who are perfect and purified from all faults who ought to seek the desert, and when they have thoroughly exterminated all their faults amid the assembly of the brethren, they should enter it not by way of cowardly flight, but for the purpose of divine contemplation, and with the desire of deeper insight into heavenly things, which can only be gained in solitude by those who are perfect. For whatever faults we bring with us uncured into the desert, we shall find to remain concealed in us and not to be got rid of. For just as when the character has been improved, solitude can lay open to it the purest contemplation, and reveal the knowledge of spiritual mysteries to its clear gaze, so it generally not only preserves but intensifies the faults of those who have undergone no correction. For a man appears to himself to be patient and humble, just as long as he comes across nobody in intercourse; but he will presently revert to his former nature, whenever the chance of any sort of passion occurs: I mean that those faults will at once appear on the surface which were lying hid, and, like unbridled horses diligently fed up during too long a time of idleness, dash forth from the barriers the more eagerly and fiercely, to the destruction of their charioteer. For when the opportunity for practising them among men is removed, our faults will more and more increase in us, unless we have first been purified from them. And the mere shadow of patience, which, when we mixed with our brethren, we seemed fancifully to possess, at least out of respect for them and publicity, we lose altogether through sloth and carelessness.