Letter 1.14

…In order to develop proper meditation it's necessary to also develop síla, a word loosely translated as virtue. It involves establishing a mental state of non-opposition, an accord, a state in which it is no longer possible for conflicts to arise which could hinder meditation. Both meditation and síla are developed - one gets more and more proficient, one's activities and perceptions more and more refined. The use of money is, inevitably, a disrupting action, and this is why monks are not permitted to use it…