The fifth way in which the desires harm the soul is by making it lukewarm and weak, so that it has no strength to follow after virtue and to persevere therein. For as the strength of the desire, when it is set upon various aims, is less than if it were set wholly on one thing alone, and as, the more are the aims whereon it is set, the less of it there is for each of them, for this cause philosophers say that virtue in union is stronger than if it be dispersed. Wherefore it is clear that, if the desire of the will be dispersed among other things than virtue, it must be weaker as regards virtue. And thus the soul whose will is set upon various trifles is like water, which, having a place below wherein to empty itself, never rises; and such a soul has no profit. For this cause the patriarch Jacob compared his son Ruben to water poured out, because in a certain sin he had given rein to his desires. And he said: Thou art poured out like water; grow thou not.’ Genesis xlix, 4. As though he had said: Since thou art poured out like water as to the desires, thou shalt not grow in virtue. And thus, as hot water, when uncovered, readily loses heat, and as aromatic spices, when they are unwrapped, gradually lose the fragrance and strength of their perfume, even so the soul that is not recollected in one single desire for God loses heat and vigour in its virtue. This was well understood by David, when he said, speaking with God: I will keep my strength for Thee. Psalm lviii, 10 [A.V., lix, 9]. That is, concentrating the strength of my desires upon Thee alone.

2. And the desires weaken the virtue of the soul, because they are to it like the shoots that grow about a tree, and take away its virtue so that it cannot bring forth so much fruit. And of such souls as these says the Lord: Vae praegnantibus, et nutrientibus in illis diebus. St. Matthew xxix, 19. That is: Woe to them that in those days are with child and to them that give suck. This being with child and giving suck is understood with respect to the desires; which, if they be not pruned, will ever be taking more virtue from the soul, and will grow to the harm of the soul, like the shoots upon the tree. Wherefore Our Lord counsels us, saying: Have your loins girt about St. Luke xii, 35. – the loins signifying here the desires. And indeed, they are also like leeches, which are ever sucking the blood from the veins, for thus the Preacher terms them when he says: The leeches are the daughters – that is, the desires – saying ever: Daca, daca. Proverbs xxx, 15.

3. From this it is clear that the desires bring no good to the soul but rather take from it that which it has; and, if it mortify them not, they will not cease till they have wrought in it that which the children of the viper are said to work in their mother; who, as they are growing within her womb, consume her and kill her, and they themselves remain alive at her cost. Just so the desires that are not mortified grow to such a point that they kill the soul with respect to God because it has not first killed them. And they alone live in it. Wherefore the Preacher says: Aufer a me Domine ventris concupiscentias. Ecclesiasticus xxiii, 6. [In the original the last two sentences are transposed.]

4. And, even though they reach not this point, it is very piteous to consider how the desires that live in this poor soul treat it, how unhappy it is with regard to itself, how dry with respect to its neighbours, and how weary and slothful with respect to the things of God. For there is no evil humour that makes it as wearisome and difficult for a sick man to walk, or gives him a distaste for eating comparable to the weariness and distaste for following virtue which is given to a soul by desire for creatures. And thus the reason why many souls have no diligence and eagerness to gain virtue is, as a rule, that they have desires and affections which are not pure and are not fixed upon God. [Lit., not pure on (or in’) God.’]