Tehzib is the shield of the people of riyāḍa (spiritual discipline). Its first subtlety is to purify service from stagnation in ignorance, custom, and himma (spiritual aspiration). Its second subtlety is the beautification of the ḥāl (spiritual state). Thus, the person does not incline toward any particular knowledge, form, or pleasure. Its third subtlety is the purification of tehzib from compulsion and passivity; it is to be aided in scholarly debates. (Ravza, 482)
Tehzib has four pillars: samt (silence), uzla (seclusion), ṣawm (fasting), and sahar (wakefulness at night). Each repels a devil. The weapon of the devil is satiety, his prison is hunger. The weapon of desire is speech, its prison is silence. The weapon of the world is mingling with people, its prison is seclusion. The weapon of the nafs (the lower self) is sleep, its prison is sahar (wakefulness). Know that excess in silence harms ḥikma (wisdom). Excess in sahar harms the senses. Excess in khalwa (spiritual retreat) leads to excessive mingling (its opposite). However, the best of affairs is the middle way.
Nevertheless, a person must struggle (mujāhada) against the following bad traits: ʿujb (self-admiration), riya (ostentation), arrogance, envy, miserliness, malice, kufr (disbelief), bidʿa (innovation), ignorance, kufrān al-niʿma (ingratitude for blessings), anxiety, complaint, despair of Allah's mercy, the qalb (the heart) being attached to worldly causes, maqām (spiritual station), desire for praise and appreciation, fear of blame, following caprice, taqlid (imitation), bowing for the world, mockery, cowardice, excessive anger, disloyalty, breaking promises, superstition, suspicion, love of wealth, love of the world, greed, profligacy, laziness, haste, postponing deeds, shamelessness, sorrow over worldly matters, fear of worldly matters, fitna (discord), obstinacy, rebellion, belittling others, hypocrisy, cunning (misusing intellect), foolishness, insatiability, inertia, love of shahawāt (desires), persistence in sin, fear of poverty, rebellion against what is decreed, deception, trickery, desire for exaltation, wishing for long life in the world for benefit, anger, hatred, arrogance, enmity, greed, living in luxury, insolence, excess, showing reverence to the rich, despising the poor, boasting, pride, rivalry, competition, arrogance before the Truth (God), engaging in useless matters, loving to talk much, affectation, adorning oneself for people, flattery, neglecting one's own faults while being preoccupied with others', loss of sorrow and khashya (awe), excessive passion for victory for one's nafs, weakness and laxity in seeking victory for Allah when one has gained victory for one's nafs, openly or secretly making enemies of one's (religious or Sufi) brothers, relying on worship, competing in plotting, betrayal, trickery, long hopes, hardness of the heart, harshness, rejoicing in the world, sorrow over what is lost, intimacy with creatures, feeling estranged when separated from them, cruelty, inconstancy, frivolity, lack of modesty and mercy.
These and similar things are attributes of the qalb (the heart), the seeds of evil in the heart, and the sprouting shoots of forbidden actions. One must avoid these and adopt their opposites. These are the praiseworthy traits. They are the source of obedience and proximity (to God). Knowledge of the limits, realities, causes, fruits, and remedies of these matters is knowledge of the Hereafter. According to them (the Sufis), tehzib is a farḍ ʿayn (an individual obligation). (Jāmiʿ, 22)
The form of tehzib at the beginning (bidāya) is to beautify action in accordance with knowledge. Its form in the abwāb (spiritual gateways) is to purify the nafs from inclining toward anything other than Allah. Its essence in muʿāmalāt (interactions) is to purify one's temperament from being led by ignorance, through the help of himma, into customs. Its degree in akhlāq (character) is to purify the nafs from evil and adorn it with virtues. Its form in uṣūl (principles) is to beautify etiquette during the sulūk (spiritual journey) with Allah. Its form in adwiya (remedies) is to purify the intellect by illuminating it with the light of sanctity.