What do you want to do sadhana for? The aim should not be the satisfaction of egoism: "I want to be a great yogi; I shall have so much power and with that power I shall establish myself in the world." All such thoughts must be thrown far away.
I must say to myself that I ruined myself, and that nobody great or small can be ruined except by his own hand. I am quite ready to say so. ... Terrible as was what the world did to me, what I did to myself was far more terrible still.
Without birth and death, and without the perpetual transmutation of all the forms of life, the world would be static, rhythm-less, undancing, mummified.