Al Salamu 'Alaykum.
Allah Ta`ala ordered Nabi sallallahu alayhi wasallam to make this Du'aa:
وَقُلْ رَّبِّ زِدْنِىْ عِلْمًا
"Oh My Rabb! Increase me in knowledge."
Despite being granted the great rank of Nubuwwat and appointed as leader of all the Ambiyaa, yet Nabi sallallahu alayhi wasallam was ordered to make Du'aa for an increase in knowledge. Knowledge('Ilm) is a Noor to safeguard ourselves, (light) through which one identifies truth from falsehood. Ignorance, on the other hand, is darkness, which conceals the hazards of this path. Thus, we must acquire knowledge.
Hadrat Sufyaan Thawri rah has outlined five stages to acquire knowledge.
First stage is Istimaa' (Listening Attentively):
When Wahi (revelation) would descend upon Nabi sallallahu alayhi wasallam, he would listen to the revelation attentively observing total concentration. The Qur-aan has recorded two orders of Istimaa`:
وَإِذَا قُرِئَ الْقُرْآنُ فَاسْتَمِعُوْا لَهُ -
"And when the Qur-aan is being recited, then pay careful attention to its recitation" and
فَاسْتَمِعْ لِمَا يُوْحى-
"Listen attentively to what is being revealed".
Paying special attention is imperative. If there is no Istimaa` then there is no guarantee that the 'Ilm acquired is that of 'Ilm e Nubuwwat. (Knowledge of Nabi sallallahu alayhi wasallam)
The angel Jibraeel descended with Wahi (revelation) to Nabi sallallahu alayhi wasallam. After listening to it, he would relate it to the Sahaabah . Allah Ta`ala, in describing the qualities of Nabi sallallahu alayhi wasallam says:
يَتْلُوْ عَلَيْهِمْ آياتِهِ
"He will recite to them the verses of the Qur'an".
The Sahaabah listened to the recitation of Nabi sallallahu alayhi wasallam with utmost devotion and concentration.
Once, whilst speaking to a Sahaabi , Nabi sallallahu alayhi wasallam grasped his shoulder and shook it. Why did Nabi sallallahu alayhi wasallam shake this Sahaabi? To ensure that he was not inattentive and paid careful attention to the words of Nabi sallallahu alayhi wasallam.
Sahaabah listened to Nabi sallallahu alayhi wasallam with complete attention. In turn, the Taabi'een heard from the Sahaabah and this sequence of narration has continued, in this manner, over the centuries until 'Ilm e Nubuwwat has reached us today.
Knowledge acquired without observing Istimaa` cannot be regarded as 'Ilm e Nubuwwat. Therefore, the Muhadditheen have placed great importance on Istimaa`.
Second stage is Insaat (silence, pondering):
Insaat refers to paying attention, pondering or being observant. Not to have a wandering mind. This means, if a student listened to the lesson inattentively, he will not grasp the intended meaning. Subsequently, there can be no guarantee that he has understood the lesson correctly. Distortions that are apparent, nowadays, are a result of not practicing upon Insaat (not paying attention or pondering over what is being said or having a wandering mind).
It has been recorded regarding a certain Muhaddith (scholar of hadith), that someone owned a strip of land close to his well but he would not grant that farmer permission to draw water from it. They were always arguing and quarrelling over this matter.
This Muhaddith had the quality of Istimaa` but he did not possess the quality of Insaat.
Someone asked him: "Why are you quarrelling so much? Everybody has the right to draw water from the well".
He replied, "It appears in the Hadith:
لاَ يَسْقِىْ أَحَدُكُمْ مَاءَهُ زَرْعَ غَيْرِه ِ
No person should use his water to irrigate the land of another.
This does appear in the Hadith. He had acquired Istimaa` but he did not possess Insaat. He did not fully understand the Hadith and he did not pay attention to its explanation.
This person then explained. "This is not the explanation of the Hadith. The correct explanation of this Hadith is, that one who has purchased a pregnant slave girl should not share the bed with her until she does not give birth to her child. The reason being, that it is the land of someone else. Therefore, one should not irrigate it."
On hearing the explanation the Muhaddith said: "May Allah reward you. Up to now I had understood the Hadith incorrectly."
It is recorded regarding yet another Muhaddith that he used to perform Witr Salaah whenever he relieved himself from the call of nature, be it during the day or at night. When asked why he did this, he replied:
"It is reported in the Hadith
اسْتَجْمَرَ فَلْيُوْتِرْ مَنِ
Whosoever relieves himself should perform Witr
The questioner told him: "This is not the actual meaning of the Hadith". He then explained the Hadith to him, "Use uneven clots of soil to clean yourself after answering the call of nature." ('Witr' mean 'uneven' and does not refer to the 'Witr Salaah')
In short, Istimaa` must be followed by Insaat.
Third stage is Hifz (remembering or memorizing):
One should remember whatever one has read, heard or understood. If the information leaves the mind then how will one be able to practise upon it and how will the chain of narration, for that part of knowledge, continue? What then will remain of 'Ilm if one heard the lesson, paid attention but did not remember it?
Fourth stage is 'Amal (practice):
One should practice on whatever one has heard attentively and remembered. If one does not practice on the 'Ilm acquired, it will be void of any benefit and blessing. An Urdu poem translates as follows:
The world will never listen to the statement of the one who does not put his own advice into practice.
Fifth stage is Nashr (preaching and imparting):
'Ilm cannot be transferred or protected without Nashr. It will remain in the confines of a closet or trunk and after a few days, it will be buried. However, embarking on preaching, without acquiring the first four stages, is of no significance. This is why Hadhrat Sufyaan Thawri rah clearly explained the five stages of knowledge so that all the stages may be adhered to.