Sri Chinmoy: One can increase one’s purity by repeating a special word or mantra. There can be no better word than “God”. One can repeat “God” while breathing in and out. While breathing in, you have to feel that at least seven breaths are coming inside each breath and offering you more life-energy. While breathing in, repeat “God”, and inside the breath try to see God seven times. And then, after some time, try to see or feel God fourteen times. In this way, try to increase your purity by increasing your count.
There is also something else which I advise my students to do. Start repeating God’s Name right from today. Today you try to repeat God’s Name twenty times most soulfully, tomorrow thirty times, the next day forty times. In this way, you bring the number up to one hundred. Then you start descending: ninety, eighty, seventy, sixty, fifty, forty, thirty, twenty, until the circle is complete. When you try to increase the number, please use your imagination to feel that your purity is increasing. And when you decrease the number, at that time please feel that you are not decreasing the number; you are only assimilating the increased purity that you have felt. While going up, try to increase your purity, and while going down try to assimilate in your system the purity-force that you achieved by repeating God’s Name.