From the Hadith of Jibril (r.a) the scholars understood Islam Has four main categories which all other areas of knowledge come under, they are Islam, Iman, Ihsan and The Signs of the Hour.
From what rasul allah (saws) mentioned of Islam we know that the laws for the Shahada, Prayer, Zakat, Fasting Ramadan, and performing the Hajj, each of them comes under the topic of Islam, the legal sciences of Fiqh (Law) and it’s codification into the legal system, Shariah, are all under this subject.
If we where to simplify the explanation of how the Legal Schools can be traced back to the prophet (saws), we can say Imam Ali and the companions who lived in Iraq where Hanafi in Law since that schools rolling revolve around their opinions, the companions who lived in Madina are Maliki, and the Shafii and Hanbali madhhabs (legal schools) are a mix of both the companions of Madina and Iraq.
This is all referring to the opinions that the founders of Islam’s four legal schools, Imam Abu Hanifa, Malik, Shaffi and Ahmad followed. The Imam’s looked into the opinions of the companions that lived in their area, and derived the methods by which these companions came up with their rulings and from all that the science of Usul al Fiqh, principles of jurisprudence, was born which every legal system on earth today relies on, the four legal schools agree on about 75% of these principles (Usul) and have differences on about 25%.
As Jibril (as) defined the Deen into four areas of knowledge, the scholars went through these four areas of knowledge in Islam and codified (to put laws or rules together as a code or system) the knowledge in them and developed sciences around studying them, like the modern sciences related to history or language, in order to preserve and study our Deen with accuracy and reliability for many later generations.
Under the topic of Iman (faith) came the laws and science behind affirming Allah’s existence, His angels, His books, His messengers, the existence of the Last Day, and the Decree of Allah, the good of it and the bad of it, which the Islamic science of Aqeedah (Creed) deals with, the two main schools of Aqeedah that were dedicated to the spread of this science are the Maturidi and Ash’ari schools, named after the respective scholars who founded them. These are the schools the wider muslim community agreed upon and spread around the Muslim world.
Most muslims know of these categories of knowledge along with the Signs of the Hour (ilm Alamat al Sa’ah) which the Mufasireen, those who wrote commentary on the Quran and Sunnah dealt with, but hardly any in the western and modern world know about the knowledge that comes under the last Islamic Science mentioned in the hadith of Jibril, that of Ihsan or human perfection.
The Deen (religion) today is only learnt from the Fuqaha (Lawyers) who are only knowledgable and qualified in Fiqh (law) and Aqeedah (creed) but not Ihsan (human perfection), so they can’t teach what they don’t know despite the fact this is the ultimate aim of Allah for mankind which He mentioned in the Quran, hence today they can’t fulfil what Allah wants.
While Islam in the hadith comes under the science of Fiqh (Law) and it’s four Madhhabs (legal schools), and Iman (faith) comes under the science of Aqeedah and it’s Madhabs (schools), Ihsan in Islam’s History came under the science of Tassawwuf, sufism.
Just as schools were created to study the other areas of knowledge, likewise schools were created to study this area of knowledge as well, the main schools dedicated to this science throughout Islam’s history were the Qadiri, Naqshbandi and Rifai, there are also many more that we can mention which developed in different parts of the Islamic world, because each person is different and each nations has it’s own identity, it is only natural that a science dealing with human character and reforming should have many different schools around the world.
Typically a scholar in Islam could be Hanafi in his Fiqh (law), Ash’ari in his Aqeedah (creed) and Rifai in his Tassawwuf (Ihsan), since they all dealt with a different area of knowledge in Islam.
Being able to quote many facts about religion is not the same as understanding it, and how it all fits together, this is like being able to quote a lot of facts about the Fiqh of wudu (ablution) and salat (prayer) but not being able to give a tafsir (explanation) of verses in the Qur’an. A fiqh (Law) manual contains a list of facts about wudu, salat, zakat, fasting and hajj while a tafsir (exegesis) contains the understanding of the Qur’an, and Allah doesn’t give understanding of the religion to every person,
يُؤْتِي الْحِكْمَةَ مَن يَشَاءُ وَمَن يُؤْتَ الْحِكْمَةَ فَقَدْ أُوتِيَ خَيْرًا كَثِيرًا وَمَا يَذَّكَّرُ إِلَّا أُولُو الْأَلْبَابِ
“He granteth wisdom to whom He pleaseth; and he to whom wisdom is granted receiveth indeed a benefit overflowing; but none will grasp the Message but men of understanding” (2:269).
So there are many Lawyers today but not many Mufasirs, people capable of explaining the religion. Under the Khalifah of Islam and through out history, Ihsan (Tasawwuf) in our academic institutions was taught alongside Fiqh (law) and Aqeedah (creed) because Allah mentions in the Qur’an that Ihsan is the mission (aim) of Rasul Allah (saws), it is the reason why He was sent, and the four reasons Allah gave for sending in the verse all aim to achieve this for man.
Imam an Nawawi wrote in his Sharh Sahih Muslim, “As far as Fiqh and Hikma (wisdom) are concerned, the former (fiqh) means to have a deep understanding of religion, whilst the latter (hikma) refers to having conscious acknowledgment of Allah Most High (ma’rifa), coupled with self-reformation, good character and abstaining from following one’s desires and falsehood (this is Tazkiya).”(Nawawi, al-Minhaj Sharh Sahih Muslim, Pg: 158-159)
The prophet (saws) said Ihsan is ‘That you worship Allah as if you see Him, for if you don’t see Him then truly He sees you.’
Tasawwuf or Tazkiya an Nafs (91:9) is mentioned in many places in the Quran, Imam Tustari said regarding verse
The Prophet (saws) said “be in this world as if you were a stranger”, Imam Ali (ra) said “Work for this world as if you will live forever, and work for the hereafter as if you will die tomorrow”, Ibn Umar (ra) said “In the evening do not anticipate the morning and in the Morning do not anticipate the evening.”
Man should build this world as if he was going to stay in it forever, so he should do what is the best and lasting for mankind in it, even though he won’t be here forever his descendants will benefit from what he wished for himself, and he should prepare for the hereafter as if He was going to die tomorrow because his end can come at any moment, and man can only take from this world what he prepared for it. Man should be a stranger to the world (not it’s people) and not contemplate in the morning what will occur by evening because he should perfect and be focused on what is occurring in that hour, moving on to his next task and perfecting it when it arrives being unattached from anything he has previously done, so he isn’t pleased with himself.
This is how man maintains his constant focus throughout the day, moving from one task to the next and perfecting it.
Before advancing scientifically, Islams scholars laid out the foundation for the Islamic state and community to live by, they codified the law, formulated the Sharia and developed the sciences and tools to investigate and understand the sources of Islam, the Qur’an and Sunnah, then they wrote about theories of law and established what the Maqasid (overall Aim and intent) of the Shariah was, which where identified and summarized in five principles known as the Five Maqasid al Shariah, in summary these five are the preservation of Religion, Life, Intellect, Procreation (family) and Property, other scholars added Justice or Happiness. Imam al- Ghazali, said regarding all the Maqasid of the Shariah, they are only for the achievement and the realization of the very benefits of man on earth.
“The muslim community responded to the magnitude of this knowledge (that Allah revealed) and the ethical imperative of living it on a daily basis with a wide range of scholarly disciplines that furnished the means to distill this vast tradition into a clear, practical answer to the question: What does Allah expect of one?”
This then is the basis for the study of sacred Law or Shari’ah in Islam: we have been ordered to follow the prophet (saws), but he is no longer alive to teach us, and All that has reached us of it came to us through men and the works they left behind, these are the tasks they spent their lives perfecting so later generations like ours could benefit from them.
This is why Muslims from the earliest times have relied on the most knowledgable of these men to take their religion from – whether in hadith, tenants of faith (Aqeedah), Qur’anic exegesis (tafsir), or the other Islamic sciences. The foremost of them were termed Imams or “Leaders”, in view of their position in each field so their place and knowledge could be accepted and followed by others.
“O ye who believe! Obey Allah, and obey the messenger and those of you who are in authority” (4:59)
“Say: “Can they who know and they who do not know be deemed equal?”(39:9)
“And so We propound these parables unto man: but none can grasp their innermost meaning save those who are aware (of Us).” (29:43)