The Prophet (s) Mentions the Condition of the Heart
Therefore the Prophet (s) said, as Bukhari narrated:
“alaa wa inna fil-jassadi mudghattan, idhaa saluhat saluhal-jassadu kulluh wa idha fassadat fassad al-jassadu kulluhu, alaa wa hiya al-qalb.”
“Surely there is in the body a small piece of meat; if it was good the whole body is good and if it is corrupted the whole body is corrupted and that is the heart.”
And he (s) said in a hadith narrated by Muslim in Bab of al-Birr,
“Inn-Allah laa yandhuru ila ajsaadikum wa laa ila suwarikum wa lakin yandhuru ila qulubikum”
which means,
“Surely Allah does not look at your bodies nor at your faces but He looks at your hearts.”
So we see here that the Prophet (s) was tieing everything to the good condition of the heart. When we leave bad manners and dress good manners, then we will have a perfect and healthy heart. That is what Allah mentioned in the Qur’an:
“yawman laa yanfa’u maalun wa laa banoon illa man att-Allaha bi qalbin saleem.” (Shu’ara, 88, 89).
“the Day wherein neither wealth nor sons will avail but only he will prosper who brings to Allah a sound heart.”
Imam Suyuti said,
“the Science of the Heart [at-Tasawwuf], and to know the heart’s diseases such as jealousy, arrogance and pride, and to leave them is an obligation on every Muslim.”
Exegesists (mufasirrun) said that jealousy (hasad), ostentation (ar-riya), hypocrisy (an-nifaq) and hatred (al-hiqd) are the bad manners which Allah mentioned in Qur’an:
“qul innamaa haramma Rabbi al-fawaahisha maa dhahara minha wa maa batan” (al-‘Aaraaf, 33)
“say the things that my Lord has indeed forbidden are: shameful deeds whether open or secret;”
Al-fawaahisha here means hatred (hiqd), envy, jealousy and hyprocisy. And Allah’s mentioning “whether open or secret” is the daleel for the need to not simply make the exterior actions correct, but to cleanse that which is hidden by a person in his heart and is known only to his Lord.
And the Prophet (s) said, as narrated in Muslim in Kitab al-Iman:
“laa yadkhulul-jannata man kana fi qalbihi mithqaala dharratin min kibar.”
which means: “No one will enter Paradise who has even an atom of pride in his heart.”
Tasawwuf is the science and knowledge whereby one learns to purify the self of the bad desires of the ego, such as jealousy, cheating, ostentation, love of praise, pride, arrogance, anger, greediness, stinginess, respect for the rich and disregard of the poor, just as one must purify the external self. The Science of Tasawwuf teaches one to look at one’s self and to purify oneself according to the Holy Qur’an and the Sunnah of the Prophet and teaches one to dress oneself with the perfect attributes (as-siffat ul-kamilah), such as Repentance (tawba), God-Consciousness (taqwa) , keeping to the Straight Way (istiqaama), truthfulness (sidq), sincerity (ikhlaas), Abstention (zuhd), Piety (war’a), Reliance on Allah (tawakkul), contentment with the decree (ar-ridaa’), surrender to Allah (at-tasleem) , good manners (al-adab), love (muhabbat), remembrance (Dhikr), watchfulness (muraqaba), and many, many other qualities too numerous to mention in detail here.
So we see that just as the Science of Hadith, mentioned in our introduction to this answer, has 35 classifications of hadith, so too does the Science of Tasawwuf have numerous classifications of both the good characteristics (akhlaaqan hassana) which are obligatory for the believer to develop, and the bad characteristics (akhlaaq idh-dhameema) which it is obligatory to eliminate, in order to attain the state of Ihsan–i.e. to become a muhsin.
From here we can see the importance of the Science of Tasawwuf and its benefit. It manifests to us clearly the essence of Islam and its lifeblood, (ruh al-islam wa qalbahu an-naabid). Islam in not only an external practice, but it also has an internal life. This is as Allah says:
“wadharu dhaahiral-ithmi wa baatinah”
Leave the outwardness of sin and its inwardness.”
Allah, Exalted and Glorious, also says in the Qur’an:
“min al-mu’mineena rijaalun sadaq maa ‘ahad-Allah ‘alayh” (al-Ahzab, 23).
“Among the Believers are men who have been true to their Covenant with Allah”
Not all believers are included in this selected group of “those who kept their covenant with Allah.” It means one can be a believer, but will not be among “those who have kept their covenant” until one has reached the state of “an-nafs az-zakkiyya” the cleansed self, and the state of Ihsan, Perfection of Behavior, which the Holy Prophet mentioned in the Holy Hadith. As we have repeated many, this is what became well-known later as the Science of Tasawwuf.
