Allah Ta’ala created this huge and expanding universe with perfection and systematic organization and created in it all what is known to Him alone. He wanted His unimaginable Attributes to get revealed. The Most Merciful and Most Magnificent Himself says in a Hadith-Qudsi:

كنت كنز مخفيه فأحببت أن أعرف فخلقت خلق

"I was a hidden treasure, I liked to get known so I created the whole creation”.

This knowledge of the Attributes of Allah Ta’ala is known as Ma’ârifat. The unimaginable vastness, height and the greatness of the Attributes of Allah Ta’ala are unlimited, whereas the whole universe is very much limited. There was a great discrepancy between the unlimited vastness, greatness and height of the Attributes of Allah Ta’ala and the limited capacity of this universe, but at the same time Allah Ta’ala wanted this immense hidden treasure of the unlimited Attributes to get revealed. If Allah Ta’ala would have revealed these Attributes directly, the universe would not have been able to tolerate the Tajaliyaat (manifestations) of these Attributes and the whole universe would have got burnt down to ashes.

Out of all the creations of Allah Ta’ala, He created man as His best creation Ashraf-ul-Makhluqât (noble creature). As Allah Ta’ala says:

لَقَدْ خَلَقْنَا الْإِنْسَانَ فِي أَحْسَنِ تَقْوِيمٍ

"We have indeed created man in the best of moulds.” (95:4)

In man Allah Ta’ala has created human heart as the best and chief Organ and the Qur’ân labels it as Qalb. As Rasulullah (Sallallahu Alaihi Wasallam) says:

ألا إنّ حِمَى اللَّهِ في أرْضِهِ مَحَارِمُهُ ألا وإنّ في الجَسَدِ مُضْغَةً إذا صَلَحَتْ صَلَحَ الجَسدُ كُلُّهُ وإذا فَسَدَتْ فَسَدَ الجَسَدُ كُلُّهُ ألا وهْيَ القَلبُ

"Indeed there is a piece of flesh in the human body, if it stays alright, the whole body stays alright, if it goes astray, the whole body goes astray. Listen with open ears: that is Qalb”. (Bukhâri Sharief)

What is Qalb

It is necessary to mention here that the word Qalb is not synonymous with the human heart which consists of muscular and connective tissues filled with some venous and arterial blood that we see in the left side of the chest, but as per the definition given in "Jalalain" (an authentic commentary of the Holy Qur’ân): Qalb is an instrument which has been given the capability of perceiving the divine Attributes.

القلب وهو مشرق اللطيفة الإنسانية و يطلق على نفس اللطيفة النورانية الربانية العالمة التي هي مهبطة الأنوار إلهية الصمدانية وبها يكون الإنسان إنساناً و بها يستعد الكتاب الأوامر و اجتناب الزواجر و هي خلاصة تولدت من الروح الروحاني و يعبر عنها الحكيم بالنفس الناطقة و لكونها هدف سهام القهر و الطف و المظهر الجمال و منشأ البسط و القبض و مبدأ المحو و الصحو و منبع الأخلاق المرضية و الأحوال الردية و كثير من الناس ذهب إلا أن تلك مضغة هي محل علم و قيل أنه في الدماغ و قيل أنه مشترك بينهما و بني ذالك على إثبات الحواس الباطنية و الكلام فيها مشهور و من راجع وجدانه أدرك أن بين الدماغ و القلب رابطة معنوية و مراجعة سرية لا ينكرها من كان له قلب أو ألقى السمع و هو شهيد (روح المعاني)

Allah Ta’ala says in the Qur’ân:

فَمَنْ يُرِدِ اللَّهُ أَنْ يَهْدِيَهُ يَشْرَحْ صَدْرَهُ لِلْإِسْلَامِ

‘Those whom He willeth to guide - He openeth their breast to ‘Islam”. (6:125)

This opening up of the breast, which is the seat of the Qalb, has been linked with understanding of guidance from Allah Ta’ala .

Rasulullah (Sallallahu Alaihi Wasallam) says in a Hadith:

"My eyes sleep, my heart does not sleep”. (Mishkat Sharief)

Rasulullah further says in a Hadith:

"lndeed, a Ghain (a sort of veil) is put on my heart and indeed I ask Istigfar (repentance) to Allah Ta’ala 100 times a day." (Muslim Sharief)

It is because of this Istigfar that these veils were getting lifted and the Qalb-i-Mubarak (blessed heart) of Rasulullah (Sallallahu Alaihi Wasallam) continued to receive higher and higher states of the Divine Knowledge.

Abu-AL-Hasan Bin Muhammad (RA) used to say:

من وقت إبن آدم إلي قيام الساعة الناس يقولون القلب القلب و أنا أحب أن أرى رجلاً يصف إلى الشقّ القلب أو كيف القلب فلا أرى

“Since the creation of Adam (AS) upto the Day of Qiyamah (the Day of Judgement), people would continue to say Qalb, Qalb. I like to see a person who would tell me as to what Qalb is and what is it like, but I don’t see anyone. People call a piece of flesh as Qalb but that is present in children as well as insane people, then what is Qalb? If I call intellect as Qalb but it is not Qalb and if I call Rooh (Spirit) as Qalb but that is also not Qalb and if I call its knowledge as Qalb but that is also not Qalb and all the constituents of Reality are related to Qalb but Qalb is something other than these.

Shah Wali-Ullah Muhaddith Delhvi (RA) says:

"Qalb is that thing by which man loves and hates."

This means according to Shah Sahib Qalb is the seat of love and hatred.

Hadhrat Haji Imdad-Ullah Muhajir Makki (RA), a great saint of recent past and Shaikh of great scholarship like Maulana Ashraf Ali Thanvi (RA), Maulana Rashid Ahmed Gangohi (RA), Maulana Qasim Nanotvi (RA) (The Founder of Darul Uloom Deoband), used to say that he has been bestowed upon by Allah Ta’ala some special blessings and these include knowledge about Qalb as well, that means Allah Ta’ala had given him such knowledge by which he could understand the Reality of Qalb and its attributes.

In other words we have different instruments for knowing different things, for example, we have thermometer to help us know the temperature of a human body, sphygmomanometer is there to tell us the blood pressure of a person. So what instrument Allah Ta’ala has created in this universe with which one can perceive Him, get His Ma’ârifat and has the capability of receiving and perceiving the rays of the Attributes of Allah Ta’ala. You have got the answer that it is the Qalb. Since it is closely associated with the human heart so the two are usually thought to be synonymous and both words are usually used for describing the same thing, though there is a difference as already explained. It is in view of this greatness and extraordinary important function of the human heart that Rasulullah (Sallallahu Alaihi Wasallam) once caught the edge of the outer curtain of Khana-Ka’aba and said:

“O Khanah Ka‘abah you are indeed great but the Qalb (Heart) of a Mumin (True believer) is greater than you" (Ibn Majah Sharief)

In this Hadith, Rasulullah (Sallallahu Alaihi Wasallam) is referring to the greatness of the human heart. This greatness of the human heart is only because of its most important function i.e., Ma’ârifat-i-Ilâhiyah. It is because of this function which makes it king of the rest of the organs (Ra’eesul Aadha).

Allah Ta’ala confirms this function of heart or Qalb by saying in the Qur’ân:

أَفَلَمْ يَسِيرُوا فِي الْأَرْضِ فَتَكُونَ لَهُمْ قُلُوبٌ يَعْقِلُونَ بِهَا أَوْ آذَانٌ يَسْمَعُونَ بِهَا فَإِنَّهَا لَا تَعْمَى الْأَبْصَارُ وَلَكِنْ تَعْمَى الْقُلُوبُ الَّتِي فِي الصُّدُورِ

"Do they not travel through the land, so that their hearts (and minds) may thus learn wisdom and their ears may thus learn to hear. Truly it is not the eyes that are blind but the hearts which are in their breasts.” (22:46)

This statement of the Qur’ân clearly reveals that it is only the heart that can perceive the Reality. These external eyes, which have a limited range of vision, cannot see the Reality. These can only see the coarse things and not the benign things. The range of the vision of heart i.e., inner vision, is infinite. The range of the vision of external eyes is no comparison to it.

Allah Ta’ala invited His beloved Prophet Muhammad (Sallallahu Alaihi Wasallam) to the highest point of humanity, the highest peak which was possible for a human being to reach but which was possible only for the greatest of the greats i.e., our beloved Prophet Rasulullah (Sallallahu Alaihi Wasallam). This was the highest status which is commonly known as Mairaj (Rasulullah’s (Sallallahu Alaihi Wasallam) midnight ascension). The capability given to the human heart (Qalb) was utilized to its maximum by the sacred Qalb-i-Mubarak of Rasulullah (Sallallahu Alaihi Wasallam) for knowing the Ultimate Reality—the Almighty Allah Ta’ala. When Allah Ta’ala mentioned this highest achievement of man, He again used the word ‘Heart’.

مَا كَذَبَ الْفُؤَادُ مَا رَأَى

"The (Prophet’s) heart in no way falsified that which he saw.” (53:11)

This again indicates that the highest perception of the ultimate Reality i.e., Allah Ta’ala was achieved again by the same instrument i.e., Qalb. In the another Qur’ânic verse, Allah Ta’ala says:

إِنَّ فِي ذَلِكَ لَذِكْرَى لِمَنْ كَانَ لَهُ قَلْبٌ أَوْ أَلْقَى السَّمْعَ وَهُوَ شَهِيدٌ

“ Verily in this is a message for any that has a heart and understanding or who gives ear and is a witness.” (50:37)

Here Allah Ta’ala clearly declares that to understand the message of the Qur’ân and to get benefit from this immense treasure, one needs to have a Qalb. Here one may say that everybody has a heart, then why does not every body understand the Qur’ân? The answer is that one needs a pure and live heart (i.e., Qalb) which can utilise its special capability of perceiving the Attributes of Allah Ta’ala and can unfold the curtain which otherwise obscures the view from the real meaning of the Qur’ânic message. Allah Ta’ala says in the Qur’ân:

فَمَنْ يُرِدِ اللَّهُ أَنْ يَهْدِيَهُ يَشْرَحْ صَدْرَهُ لِلْإِسْلَامِ وَمَنْ يُرِدْ أَنْ يُضِلَّهُ يَجْعَلْ صَدْرَهُ ضَيِّقًا حَرَجًا كَأَنَّمَا يَصَّعَّدُ فِي السَّمَاءِ كَذَلِكَ يَجْعَلُ اللَّهُ الرِّجْسَ عَلَى الَّذِينَ لَا يُؤْمِنُونَ

“ Those who Allah Ta’ala willeth to guide, He openeth their breast to Islam. Those whom He willeth to leave straying- He maketh their breast close and constricted As if they had to climb up to the skies, thus Doth Allah Ta’ala lay abomination on those who refuse to believe” (6:125)

In this verse Allah Ta’ala has linked His bestowing of guidance to somebody with opening of his breast for Islam. Since breast is the seat of Qalb, so its opening is the opening of Qalb for Islam. This process has been described as the enlightening of the heart with the Eternal Light. As Rasulullah (Sallallahu Alaihi Wasallam) while explaining the above mentioned Qur’ânic verse says:

“Ibn-Masood (RA) narrated that Rasulullah (Sallallahu Alaihi Wasallam) recited ( the above mentioned verse) “ those whom Allah Ta’ala willeth to guide, He openeth their breast to Islam" then Rasulullah (Sallallahu Alaihi Wasallam) said when the light (External) enters the breast it opens. He was asked, is there any sign by which this (Eternal Light) can be appreciated? he said,“ yes forsaking the world of deception and inclination towards the eternal world (Hereafter) and preparation for death.” (Mishkat)

In this Hadith, Rasulullah (Sallallahu Alaihi Wasallam), has clearly pointed out that enlightening of the heart with the Eternal Light means the opening of the heart. From the Aayat quoted above and the Hadith the inference can easily be derived that it is the enlightened heart (Qalb} that gets the guidance of Allah Ta’ala and can, therefore, perceive the Truth and the ultimate Reality. Now the question arises if the heart is not enlightened by this Eternal Light, then what?

Zulmat and Nur (Darkness and Light)

The opposite of the Light is Darkness. The Qur’ân has mentioned these as Nur and Zulmat respectively.

The heart which is not illuminated by the Eternal Light is said to be in darkness or blind as Allah Ta’ala says in the Qur’ânic verse, already quoted, that their (external) eyes are not blind but their hearts are blind. This darkness of heart (Qalb) is called Zulmat whereas the Eternal Light which enlightens the heart is called Nur. Allah Ta’ala reveals this in the Qur’ân:

اللَّهُ وَلِيُّ الَّذِينَ آمَنُوا يُخْرِجُهُمْ مِنَ الظُّلُمَاتِ إِلَى النُّورِ وَالَّذِينَ كَفَرُوا أَوْلِيَاؤُهُمُ الطَّاغُوتُ يُخْرِجُونَهُمْ مِنَ النُّورِ إِلَى الظُّلُمَاتِ أُولَئِكَ أَصْحَابُ النَّارِ هُمْ فِيهَا خَالِدُونَ

“ Allah Ta’ala is the protector of those who have faith: From the depths of darkness He leads them forth into light.” (2:257)

Now if we recapitulate the Qur’ânic revelations and the saying of Rasulullah (Sallallahu Alaihi Wasallam) already quoted in the previous lines, we can easily come to the conclusion that the function of the Qalb is to perceive the Divine Attributes, appreciate the Ultimate Reality and to understand the message of the Qur’ân. If the Qalb is plunged into darkness, then obviously it is deprived of these functions and will be as good as dead. So, when a person has his Qalb in the depths of darkness, he cannot know the Truth, cannot understand the significance of the eternal life, cannot achieve Ma’ârifat of Allah Ta’ala and cannot even smell the fragrance of the meaning of the Qur’ân, not to speak of tasting and assimilating it. This person is like a frog in a well that is totally unaware of the vastness of this universe, as this frog thinks that the well in which it lives is the only world.

In medical terms, we are aware of two states of mind, conscious and subconscious states. Normally, in the majority of people the major portion of mind remains in subconscious state and only a little portion attains conscious state or else one can say that the major portion of mind remains in darkness and only a little portion gets enlightened. It is the conscious portion of mind that is utilised by man, therefore, the major portion of his mind remains un-utilised.

If one talks of neuro-anatomy and physiology of human brain, the modern medical science has yet succeeded in knowing the anatomy and physiology of only few centres of brain, a tip of an iceberg. The mystery of tremendous ocean of the brain potential remains unexplored to the scientists of Medicine even today.

The same does not hold true about the great muslim research scholars. As Allah Ta’ala took them from the depths of darkness forth into the light which enlightened their subconscious state, converting that into conscious state. With this enlightenment their ratio of conscious state and sub-conscious state got reversed, their conscious state of mind became so powerful that it gave them immense vision which could penetrate all the curtains that otherwise lie between the Reality and the Mind and between, the Qalb and the external eyes.