Hakimul Ummah Mawlana Ashraf Ali Thanvi (upon him be the Mercy of Allah) states:

“After rectification of beliefs and external acts, it is compulsory (fardh) upon every Muslim to rectify his esoteric (inner/baatin) acts. Numerous Quranic verses and untold number of hadiths explicitly indicates the obligation (fardhiyah) of this.

Who is not aware that the Quran and hadiths is explicit regarding the significance of abstinence (zuhd), contentment (qana’ah), humbleness (tawadu’), sincerity (ikhlas), patience (sabr), gratitude (shukr), love of Allah (hubb ullah), contentment with the Decree (ridha bil qadha), trust (tawakkul), submission (tasleem), and so on, while they emphasize the attainment of these noble attributes?

And who is not aware that the Quran and hadiths condemn the opposites of these noble qualities: love for the world (hubbud dunya), covetousness (hirs), arrogance (takabbur), ostentation (riya), lust (shahwah), anger (ghadab), jealousy (hasad), and so on, and warns against them?

Is there no doubt that noble qualities have been commanded, and the base traits forbidden? This is the actual meaning of reforming the esoteric acts. This is the primary purpose of the spiritual path (tariqah). That it is obligatory (fardh) is without a doubt an established fact.” (Haqiqatut Tariqah)

Khawjah Mu’inud Deen Chisti said:

“He who adheres to the Shari’ah, obeys its commands, and refrains from sin progress in spiritual rank. All progress depends upon adherence to the Shari’ah.”

Junaid al-Baghdadi said:

“All paths (to Allah) besides the strict following of the Messenger of Allah (sallalahu alaihi wa sallam) are closed to mankind.”

Hakimul Ummah states:

“Now that the nature and reality of tasawwuf and suluk have become clear, it will be understood that unveilings (kashf) and miracles (karamat) are not necessary. It [tasawwuf] does not promise success in worldly affairs; nor does it assert that one’s work will be accomplished by means of amulets (ta’widh) and potions; nor does it claim that one will necessarily be successful in court cases by means of invocations (dua). It does not promise increase in one’s earnings, nor does it promise one cure from physical ailments. It does not foretell future events. It does not contend that the seeker’s (mureed) reformation will be achieved by the spiritual focus (tawwajuh) of the sheikh. Extraordinary feats are not organic to tasawwuf. It does not contend that the one who treads this path will not be afflicted by thoughts of sin, nor does it claim that the seeker will automatically (without effort) engage in worship. It does not promise total self-annihilation (fanaa) so that one is not  aware even of one’s presence. It does not promise experiences of states of ecstasy and spiritual effulgence through spiritual exercises (dhikr and shughl), nor does it claim that one will see beautiful dreams and wonderful visions.

None of the above are aims of tasawwuf. The good pleasure (ridwan) of Allah Most High is.”

(adapted from The Path to Perfection by Mawlana Masihullah Khan May Allah have Mercy on him)