While walking, a saintly person is careful not to kill any tiny creatures on the ground. Similarly, he filters his drinking water through cloth to avoid swallowing small creatures living within the water. Speaking untruths simply for sense gratification is detrimental to devotional service and should be avoided. Speaking impersonal philosophy and glorifying the sense gratification of the material world, even that found in heavenly planets, contaminates the heart and must be avoided by those desiring perfection in the loving service of the Lord. By serious consideration one can understand that any activity other than devotional service to Lord Kṛṣṇa has no ultimate value; therefore one should exclusively engage in the purified activities of Kṛṣṇa consciousness.