One of the most important guiding principles in the Sufi way of life is adab, which can be translated as courtesy, respect, appropriate behavior. Adab is not mere formality; it helps to create the context in which we develop our humanness. Every situation and relationship has its own adab: between students on the path, in relation to family members and elders, in relation to one's shaikh.
— Kabir Helminski, The Knowing Heart