Wisdom is purified by morality, and morality is purified by wisdom: where one is, the other is, the moral man has wisdom and the wise man has morality, and the combination of morality and wisdom is called the highest thing in the world.(Sonadanda Sutta, DN. NO. 4; 'The Long Discourses of the Buddha' (Tr. Maurice Walshe), Wisdom Publications, Boston, 1995, p. 131.