Of imperfections with respect to spiritual envy and sloth.
WITH respect likewise to the other two vices, which are spiritual envy and sloth, these beginners fail not to have many imperfections. For, with respect to envy, many of them are wont to experience movements of displeasure at the spiritual good of others, which cause them a certain sensible grief at being outstripped upon this road, so that they would prefer not to hear others praised; for they become displeased at others’ virtues and sometimes they cannot refrain from contradicting what is said in praise of them, depreciating it as far as they can; and their annoyance thereat grows  because the same is not said of them, for they would fain be preferred in everything. All this is clean contrary to charity, which, as Saint Paul says, rejoices in goodness.  And, if charity has any envy, it is a holy envy, comprising grief at not having the virtues of others, yet also joy because others have them, and delight when others outstrip us in the service of God, wherein we ourselves are so remiss.
2. With respect also to spiritual sloth, beginners are apt to be irked by the things that are most spiritual, from which they flee because these things are incompatible with sensible pleasure. For, as they are so much accustomed to sweetness in spiritual things, they are wearied by things in which they find no sweetness. If once they failed to find in prayer the satisfaction which their taste required (and after all it is well that God should take it from them to prove them), they would prefer not to return to it: sometimes they leave it; at other times they continue it unwillingly. And thus because of this sloth they abandon the way of perfection (which is the way of the negation of their will and pleasure for God’s sake) for the pleasure and sweetness of their own will, which they aim at satisfying in this way rather than the will of God.
3. And many of these would have God will that which they themselves will, and are fretful at having to will that which He wills, and find it repugnant to accommodate their will to that of God. Hence it happens to them that oftentimes they think that that wherein they find not their own will and pleasure is not the will of God; and that, on the other hand, when they themselves find satisfaction, God is satisfied. Thus they measure God by themselves and not themselves by God, acting quite contrarily to that which He Himself taught in the Gospel, saying: That he who should lose his will for His sake, the same should gain it; and he who should desire to gain it, the same should lose it. 
4. These persons likewise find it irksome when they are commanded to do that wherein they take no pleasure. Because they aim at spiritual sweetness and consolation, they are too weak to have the fortitude and bear the trials of perfection.  They resemble those who are softly nurtured and who run fretfully away from everything that is hard, and take offense at the Cross, wherein consist the delights of the spirit. The more spiritual a thing is, the more irksome they find it, for, as they seek to go about spiritual matters with complete freedom and according to the inclination of their will, it causes them great sorrow and repugnance to enter upon the narrow way, which, says Christ, is the way of life. 
5. Let it suffice here to have described these imperfections, among the many to be found in the lives of those that are in this first state of beginners, so that it may be seen how greatly they need God to set them in the state of proficients. This He does by bringing them into the dark night whereof we now speak; wherein He weans them from the breasts of these sweetnesses and pleasures, gives them pure aridities and inward darkness, takes from them all these irrelevances and puerilities, and by very different means causes them to win the virtues. For, however assiduously the beginner practises the mortification in himself of all these actions and passions of his, he can never completely succeed–very far from it–until God shall work it in him passively by means of the purgation of the said night. Of this I would fain speak in some way that may be profitable; may God, then, be pleased to give me His Divine light, because this is very needful in a night that is so dark and a matter that is so difficult to describe and to expound.
The line, then, is:
In a dark night.
-  [Lit., and, as they say, their eye (el ojo) grows’–a colloquial phrase expressing annoyance.]
-  1 Corinthians xiii, 6. The Saint here cites the sense, not the letter, of the epistle.
-  St. Matthew xvi, 25.
-  [Lit., they are very weak for the fortitude and trial of perfection.’]
-  St. Matthew vii, 14.