The desire-nature is the worst foe. It is very difficult to be armed against it, since, firstly, it is an internal foe, and it is almost impossible to guard the house against a thief co-tenant; and, secondly, it is a lovely foe, and a man is blind to the defects of his beloved, whose shortcomings take on the appearance of merits. Such being the case, the desire-nature may ere long hurl a man unawares to the lowest depth of degradation. If you ponder well, you will find it at the root of all the troubles that beset man in the past or may beset him in the future. This being the foe, one should intelligently strive to overcome it. It is improper to overcome it all at once, as it is a vehicle and instrument of the Soul; nor is it proper to let it go wholly unbridled, in view of the probable dangers. So the disciple needs a middle course, and it is this: You should strengthen it to the extent of enabling it to perform its duties; you should weaken it to the measure of preventing the chance of its leading you astray. Anything besides this rule is objectionable. It is reported in sacred tradition that on seeing Abdullâh Masûd, who had by ascetic practices weakened his body, his feet having become incapable of motion, his eyes having sunk in their sockets, Mohammad said, “O Abdullâh, be warned! Thy desire-nature has claims on thee.” So the conclusion is that the desire-nature should be dis­ciplined by knowledge, so that it may neither overcome (nor disobey) thee, nor be itself destroyed.

The middle course consists in restraining the desire-nature by temperance. There are three ways of thus subduing it: (a) withholding gratification; … (b) imposing religious observances; (c) invoking the Divine help for mastery over it. If you follow this threefold method, the desire-nature will be amenable to discipline.—Letter 83.