Question: How can we keep the mind pure when we are not concentrating or meditating?

Sri Chinmoy: The best thing you can do is learn a few spiritual songs and sing them to yourself in silence while you are working or driving your car or doing anything that does not require mental concentration. While you are chanting in silence, your mind is being purified because your soul is coming forward. When you chant or sing, try to feel that the Supreme is listening. Otherwise, the chant will become a mere mechanical habit. So feel that there is a listener — not a human listener, but the Supreme Himself — listening inside your heart. When you feel that you have a divine listener, you will get more inspiration; you will be surcharged with boundless inspiration and endless inner joy. When you feel the presence of the Supreme inside your heart, He will bless you with utmost joy and pride. He will do everything to transform, purify, illumine and liberate your mind.

From:Sri Chinmoy,Mind-confusion and heart-illumination, part 1, Agni Press, 1974
Sourced from https://srichinmoylibrary.com/mch_1