dhunoti dhvāntam arkavat

yasya-of whom; narayanah devah-the Supreme Personality of Godhead, Narayana; bhagavan-the Lord; hrt-gatah-in the core of the heart; sada-always; bhaktya-by devotional service; kevalaya-alone; ajnanam-ignorance; dhunoti-cleans; dhvantam-darkness; arka-vat-as the sun.