Sri Aurobindo
Letters of Sri Aurobindo
Volume 3
What Krishnaprem writes (I have not read it yet) is perfectly true that purification of the heart is necessary before there can be the spiritual attainment. All ways of spiritual seeking are agreed on that. Purification and consecration are two great necessities of sadhana. It is not a fact that one must be pure in heart before one can have any Yogic experience at all, but those who have experiences before purification is done run a great risk. It is much better to have the heart pure first, for then the way becomes safe. Nor can the Divine dwell in one’s consciousness, if that consciousness is obscure with impurity. It is for the same reason that I advocate the psychic change of the nature first – for that means the purification of the heart, the turning of it wholly to the Divine, the subjection of the mind, of the vital passions, desires, demands, of the physical instincts to the control of the inner being, the soul. What Krishnaprem calls intuitions I would describe as psychic intimations or, as some experience it, the voice of the soul showing the outer members what is the true thing to be done. Always, when the soul is in front, one gets the right guidance from within [as to] what is to be done, what avoided, what is the wrong thing or the true thing in thought, feeling, action. But this inner intimation emerges in proportion as the consciousness grows more and more pure.
I never intended that Sarat should stay here; he came for 
darshan and sat down here without a “by your leave”. I allowed him to remain for a while to see if he got any profit out of it; afterwards came his repeated illness and he somehow stuck on till one. What I meant by some concrete method was things like repetition of a mantra, pranayama, asana, etc. He has been doing these things even here or some of them at least; it is the only thing he really understands (or misunderstands?); but purification of the heart he has not been capable of doing. What I mean by subtle methods is psycho-logical, non-mechanical processes – e.g., concentration in the heart, surrender, self-purification, working out by inner means the change of the consciousness. This does not mean that there is no outer change – the outer change is necessary but as a part of the inner change. If there is impurity and insincerity within, the outer change will not be effective, but if there is a sincere inner working, the outer change will help it and accelerate the process. What use is Sarat’s eating less except for his body’s health? But if a man seeks to restrain and get rid of his greed for food or attachment, (not by starvation, though) then he is doing something useful to his sadhana.
Jashwant’s case is different. His main stumbling-block was ambition, pride, vanity, the desire to be a big yogi with occult powers. To try to bring down occult powers into an unpurified mind, heart and body – well, you can do it if you want to dance on the edge of a precipice. Or you can do it if your aim is not to be spiritual but to be an occultist, for then you can follow the necessary methods and get the help of the occult powers. But the occult spiritual forces and masteries can be called down or [can] come down without calling only if that is quite secondary to the true thing, the seeking for the Divine, and if it is part of the Divine plan in you. Occult powers can only be for the spiritual man an instrumentation of the Divine Power that uses him, they cannot be the aim or an aim of his sadhana. I don’t know who started Jashwant on this false path or whether he hit on it himself; many people here have a habit of doing yoga according to their own ideas 
without caring for the guidance of the Guru – from whom, however, they expect an entire protection and success in sadhana even if they prance or gambol into the wrongest paths possible.
Of course, renunciation of sex is indispensable for the purification you seek – the heart must be pure and consecrated to the Divine. There must be no turn left that side. As for food, well, that is not so much a purification of the heart as of the vital in the physical, but it is of course very helpful to get control there. The purification of the heart is the central necessity, but a purification of the mind, vital and physical is also called for. But the most important thing for purification of the heart is an absolute sincerity. No pretence with oneself, no concealment from the Divine, or oneself, or the Guru, a straight look at one’s nature and one’s movements, a straight will to make them straight. It does not so much matter if it takes time; one must be prepared to make it one’s whole life-task to seek the Divine. Purifying the heart means after all a pretty considerable achievement and it is no use getting despondent, despairful, etc., because one finds things in oneself that still need to be changed. If one keeps the true will and true attitude, then the intuitions or intimations from within will begin to grow, become clear, precise, unmistakable and the strength to follow them will grow also. And then before even you are satisfied with yourself, the Divine will be satisfied with you and begin to withdraw the veil by which he protects himself and his seekers against a premature and perilous grasping of the greatest thing to which humanity can aspire.