Rupa Gosvami has introduced this system of regulative principles which I have taught to you also. These regulative principles, such as rising before 4 a.m. for mangala aratrika, chanting 16 rounds minimum on beads daily, reading books, going for the street sankirtana, preaching to anyone and everyone, offering the prasadam, like that, these principles of devotional service are there to safeguard us from maya's attack by keeping us always enthusiastic.
Letter to Dhananjaya, 31 December, 1972