It arises from reverence. The reverence (taʿẓīm) for the Real (al-Ḥaqq) and His symbols stems from taqwa (God-consciousness). Whoever disrespectfully tramples upon the witnesses of the Real has no share on the path of Sufism (taṣawwuf). Neither intoxication (sukr) nor galaba (overwhelming spiritual state), nor any ḥāl (spiritual state) can prevent a seeker from adhering to proper etiquette (adab). For adab is their custom, and custom is something close to nature. As long as life continues, it is impossible for the natures of living beings to be entirely eliminated in any state (in the sense of transformation). Therefore, as long as their personalities exist, the act of observing adab in all their states persists. Sometimes this is done with effort (takalluf), and sometimes without effort (spontaneously). (The Sufis) preserve the rules of conduct with effort in the state of sobriety (ṣaḥw). When in the state of intoxication (sukr), Allah Most High preserves adab upon them. (Hujwīrī, 401–402)
Adāb al-faqīr fī faqr (the etiquette of the poor in their poverty): Know that there are certain etiquettes that the poor person must observe inwardly, outwardly, among people, and in their behavior. The inward etiquette is that the servant should not despise the poverty that Allah Most High has given as a trial. That is, even if he dislikes poverty, he should not despise the act of Allah. It is like someone who undergoes bloodletting: he finds the process painful and thus dislikes it, but he does not look down upon the bloodletter or the instrument; rather, he is grateful to the bloodletter. This is the lowest degree (of adab in poverty). This is obligatory; to do otherwise is forbidden and nullifies the reward of poverty. The Messenger of God (peace be upon him) said: "O poor ones! Be content in your hearts with what Allah has decreed for you, so that you may attain the reward of poverty. Otherwise, you will be deprived of this reward." (Daylamī, 291) This is the meaning of the ḥadīth.
A higher degree than this is not to despise poverty and to be content with it. To desire poverty, to rejoice in it because one knows the dangers of wealth, to rely upon Allah inwardly, to trust without doubt that He will provide what is necessary, and not to ask for more than what is needed—this is a superior degree. ʿAlī (may Allah ennoble his face) said: "Indeed, Allah Most High has certain punishments due to poverty, and also certain rewards due to poverty. Among the signs that poverty brings reward is that one improves his character through it, obeys his Lord, does not complain about his ḥāl (state), and gives thanks for being a servant. Among the signs that poverty leads to sin is to disparage it, to complain about one's Lord by abandoning obedience, and to be displeased with divine decree and destiny (qaḍāʾ and qadar). This shows that not every poor person is praiseworthy. Rather, the praiseworthy poor person is the one who is content with Allah's decree, rejoices in poverty, and is content because he knows its fruits." It has been said: "Whenever something from the world (dunyā) is given to a servant, it is said to him: 'Take this thing on three conditions: preoccupation, sorrow, and a lengthy reckoning (in the Hereafter) for what has been given.'"
As for the outward etiquette of poverty, it is to display chastity and dignity, not to make one's poverty known by complaining, but rather to conceal it, and even to conceal the fact that one is concealing it. (Iḥyāʾ, IV, 253–254)
In terms of adab, people are divided into three: the people of the world (ahl al-dunyā), the people of religion (ahl al-dīn), and among the people of religion, the elect (ahl al-khuṣūṣiyya, the select). Most of the adab of the people of the world consists of eloquence, rhetoric, learning sciences, memorizing the news of kings (mulūk) and the poetry of the Arabs. Most of the adab of the people of religion, along with worldly sciences, is to train the nafs (lower self), and the limbs...