This essay explores the concept and application of self-purification from the perspective of the teachings of Imam ‘Alī. The sermons, letters and traditions of Imam ‘Alī ibn Abī Tālib as recorded in Nahj al-Balāgha, will be examined in an effort to derive methods and aspects pertaining to self-purification. Of course it is noteworthy to mention that this esteemed masterpiece has been analyzed from many angles by a variety of scholars. Even assemblies and conventions have been established to celebrate the renowned text and to better analyze its various dimensions, including the mystical aspects. And the text is also studied in Islamic seminaries.
Meaning of “Self-Purification”
Tazkiyyah, or self-purification, also sometimes described as self-building or even jihād al-nafs (the combat with the self) i.e. the struggle to rid one’s self of impure and immoral attributes and to gain control of one’s desires and lustful inclinations. 
Its Role in ‘Irfān
Islamic mysticism constitutes a multitude of dimensions, but success in the purest fashion is only attainable via self-purification. For instance, the concept of remembrance or dhikr is very prevalent and well practiced amongst mystics, in particular those of Súfí orientation. But, the reality is that certain dhikrs, in particular the asmā’ al-a’dham have powerful effects. Of course, mystical knowledge, including powerful dhikrs are not limited to wayfarers of spirituality and Islamic mysticism, and have been noted to have been used by individuals, human and jinn, with impure hearts or even malicious intent. However, according to the teachings of Islamic mysticism, true benefit of the spirituality and power of the Divine Names is only available to purified souls.
As Mentioned in Quran
God has mentioned this concept throughout the holy Quran and has touched on the topic of purifying the nafs in several places. In Sura al-Shams verses 7-10 it states: by the soul and Him who fashioned it, and inspired it with [discernment between] its virtues and vices: one who purifies it is felicitous, and one who betrays it fails. Also in verse 14 of Sura al-‘A`lá it mentions: Felicitous is he who purifies himself.
The Goal and Purpose
Therefore the overall goal of self-purification is achieving proximity to God and transforming indefinite human potential into paramount success of human reality, which transcends worldly boundaries through the cosmos and reflects the immaculate perfection of Divine light in the form of al-insān al-kāmil (the Perfect Man). 
Mystical Dimensions of ‘Alī ibn Abī Tālib
After the Prophet Muhammad (peace be upon him), Imam ‘Alī ibn Abī Tālib (peace be upon him) is considered to be the manifestation of the most perfect human being in the Muhammadan mode. He was well known for piety and faith and referred to as Amīr al-Mu’minīn (The Commander of the Faithful). His mystical dimensions are unparalleled and quite frankly speak for themselves. The efforts of Súfís and Mystics, past and present to attribute their teachings, leaders, sheikhs and principles to Imam ‘Alī are well documented and are a testament to his spiritual perfection. In addition to that the Prophet himself explicitly declared ‘Alī’s authority and made known his spiritual and knowledgeable presence. Famous traditions can be found amongst Sunni and Shīa Hadith books. Some traditions related from the Prophet in this regard are:
Overview of Nahj al-Balāgha
Sayyed Muhammad al-Radhī (406AH/1015AD), the brother of Sayyed al-Murtadhā (436AH/1044AD) was a well-known scholar of his time. Both were students of the legendary Shaykh al-Mufīd (413AH/1022AD). The most important work of al-Radhī is the compilation of selected sermons, letters and maxims of Amīr al-Mu’minīn ‘Alī (peace be upon him) which was titled Nahj al-Balāgha. Some of the meanings of Nahj (an Arabic word) include: ‘road’ or ‘method’. Balāgha is defined as meaning ‘eloquence’. It is often translated as ‘Peak of Eloquence’. He selected 241 sermons, 79 letters, and 489 sayings. Those numbers vary in different editions of Nahj al-Balagha. The number of sermons varies from 238 to 241 and the number of letters varies from 77 to 79, whereas sayings vary from 463 to 489. Al-Radhī was quoted as having said:
Through him hidden delicacies of eloquence and rhetoric came to light, and from him were learnt its principles and rules. Every speaker and orator had to tread on his footprints, and every eloquent preacher availed of his utterances. Even then they could not equal him, for the credit for being the first and foremost remained with him, because his utterances were those that carried the reflection of Divine knowledge and savour of the Prophet’s utterances. Accordingly I acceded to their request, as I knew that it meant great reward, handsome reputation and a treasure of recompense. The object of this compilation is that I should bring forth Amīr al-Mu’minīn greatness and superiority in the art of rhetoric which is in addition to his countless qualities and innumerable distinctions, and to show that he has risen to the highest pinnacle of this attainment, is singular among all those predecessors whose utterances are quoted here and there, whereas his own utterances are like an onrushing and irresistible stream, and such a treasure of subtleties in language is unmatched.
Base Levels of Self-Purification
As the foundation of Islamic mysticism, self-purification has many levels. Some levels pertain to the aspirant who is in the early stages of realization of a need to better his or her self, while other levels encompass the refined wayfarer who anticipates pursuing higher realms of spirituality. Either way, the most base level to self-purification and self-building begins with the performance of obligatory deeds and abstention from cardinal sins and then all sins great or small.
Regarding the tainted status of the sinner and one who is disobedient to God’s command, Imam ‘Alī has expressed this in Sermon 199, where he reproaches the sinful actions of Mu’awiyah:
“By Allâh, Mu`awiyah is not more cunning than I am, but he deceives and commits evil deeds. Had I not been hateful of deceit I would have been the most cunning of all men. But (the fact is that) every deceit is a sin and every sin is disobedience (of Allâh), and every deceitful person will have a banner by which he will be recognized on the Day of Judgment.”
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 Holy Quran. Translated by Ali Quli Qara’i. 2nd revised edition. ICAS Press. 2005. Pg 846
 Mutahhari, Murtadhā. Goal of Life. Be’that Foundation. 1982?. Islamic Republic of Iran. Ch 1
 Masterton, Rebecca. The dimensions of Imām ‘Alī ibn Abī Tālib (as). Islamic College for Advanced Studies. Islamic Mysticism module. 2009. Content 2.3
 Al-Mufid, Shaykh. Kitāb AL-Irshād The Book of Guidance. Ansariyan Publication. 1986?. Qom, Islamic Republic of Iran. Translated by I.K.A Howard
 Al-Naraqi, M.M. Jami’ al-Sa’adat (The Collector of Felicities). ?. Mu’assasat al-A’lami.