And as for the madaahib  then they are the opinions of the people of knowledge and their understanding of some of the masaa’il (issues) and their deductions. And the following of these opinions and deductions and understandings was not made obligatory by Allaah and His Messenger on anyone. For verily in them is that which is correct and that which is wrong and is not exclusively correct except that which is established or confirmed upon the Messenger of Allaah . And much of what the Imaams chose as their opinion in a particular was changed by them after the truth was manifested to them. 
So with this whomsoever desires to enter the deen of Islaam and desires to be honored with Imaan then there is nothing upon him other than the testification that nothing is worthy of worship of Allaah and that Muhammad is the Messenger of Allaah and to establish the five prayer and to give the zakaah and to fast the month of Ramadaan and to make Hajj to the House if he is capable to do so.
And as for the following of a madhab from the madaahib or other than them then it is not obligatory nor is it recommended. And it is not upon a Muslim to necessitate oneself to a particular one from them, in fact the one who necessitates himself to a particular madhab from them then he is a fanatical blind follower who is in the wrong. And he is from amongst those who divided the religion and became groups, and indeed Allaah has prohibited division in the religion.
So Allaah says (which means):
"Verily, those who divide their religion and break up into sects (all kinds of religious sects), you (O Muhammad ) have no concern in them in the least." [Surah Al-An'am (The Cattle) Verse 159 ]
And He says (which means):
"and be not of AlMushrikun (the disbelievers in the Oneness of Allaah, polytheists, idolaters, etc.). Of those who split up their religion , and became sects, [i.e. they invented new things in the religion (Bid'ah), and followed their vain desires], each sect rejoicing in that which is with it." [Surah Ar-Rum (The Romans) Verses 31 to 32 ]
So the deen of Islaam is One. There is no madhab or path which is obligatory to follow except the path of the Messenger of Allaah and his guidance. And Allaah says (which means):
"Say (O Muhammad ): "This is my way; I invite unto Allaah with sure knowledge, I and whosoever follows me (also must invite others to Allaah ) with sure knowledge. And Glorified and Exalted be Allaah. And I am not of the Mushrikun ." [Surah Yusuf (Joseph) Verse 108 ]
And disputes have increased among those who blindly follow without knowledge these madaahib. And Allaah says (which means):
"And obey Allaah and His Messenger, and do not dispute (with one another) lest you lose courage and your strength depart, and be patient. Surely, Allaah is with those who are As-Sabirin (the patient ones, etc.)." [Surah Al-Anfal (The Spoils of War) Verse 46 ]
And He orders unity and to firmly cling to His book.
"And hold fast, all of you together, to the Rope
of Allah (i.e. this Qur'aan), and be not divided among yourselves."
Aali Imran (The Family of Imran) Verse
 [Translators Footnote] pl. of
madhab, Madhab: way, juristic school of thought
 The writer is establishing some known rules that are with the students of knowledge: The matters in the madhaahib are said upon opinions only and they are matters of deductions and they do not have with them a text and it is not waajib (mandatory) to follow them but it is permissible to follow them if one thinks them to be correct.
Author: Muhammad Sultan al-Ma’soomi
Source: Hal al-Muslim Mulzim bittibaa’I madhab mu’aiyyin
Translated by : Kashif bin Hazoor Khan as-Salafi’
Footnotes by : Shaykh saleem al-Hilaali
Taken From: Theerighteouspath.com