Srila Prabhupada - Vedic Teachings

  "Cleanliness is essential for making advancement in spiritual life. There are two kinds of cleanliness: external and internal. External cleanliness means taking a bath, but for internal cleanliness one has to think of Kṛṣṇa always and chant Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare. This process cleans the accumulated dust of past karma from the mind." (BG 13.8-12, Purport) "But as the days of this Kali-yuga will make progress, this system of hygienic cleanliness, cleanliness both inside and outside Outside by taking bath, inside by becoming Kṛṣṇa conscious—two kinds of cleanliness. Simply if we take bath with soap outside, and inside all rubbish things, that is not cleanliness. Cleanliness means bahyābhyantaraḥ. Bahya means outside, without. Abhyantara means inside. Unless we are clean, unless we are pure, how we can make advance to approach the Supreme? The Supreme is described as the purest. In the Bhagavad-gītā Arjun