Ruling on taking lightly the matter of ruling in accordance with the sharee’ah of Allaah and not applying it
Question

                Many Muslims take lightly the matter of ruling according to something other than the sharee’ah of Allaah. Some believe that taking this matter lightly does not have any impact on their adherence to Islam, and others think it is permissible to rule according to something other then that which Allaah has revealed and do not care about the consequences of that. What is the ruling on this?.
Praise be to Allah.
    This matter is subject to further discussion, which is that 
    the one who rules according to something other than that which Allaah has 
    revealed, knowing that it is obligatory to rule according to that which 
    Allaah has revealed and that he is going against sharee’ah, but he thinks 
    that this is permissible and that there is nothing wrong with it and that it 
    is permissible for him to rule according to something other than the 
    sharee’ah of Allaah, is a kaafir in the sense of major kufr, according to 
    all scholars. This applies to ruling in accordance with man-made laws which 
    have been invented by men, be they Christians or Jews or anyone else, if he 
    claims that it is permissible to rule according to them, or that they are 
    better than the rulings of Allaah, or that they are equal to the rulings of 
    Allaah, and that man has the choice: if he wishes he may rule according to 
    the Qur’aan and Sunnah, and if he wishes he may rule according to man-made 
    laws. The one who believes that is a kaafir according to scholarly 
    consensus, as stated above. 

    But if a person rules according to something other than that 
    which Allaah has revealed because of his whims and desires or because of 
    some worldly interest he may achieve, knowing that he is disobeying Allaah 
    and His Messenger, and that he is committing a great evil and that what he 
    should do is rule according to the laws of Allaah, he is not guilty of major 
    kufr because of that, but he has committed a great evil, major sin and minor 
    kufr, as stated by Ibn ‘Abbaas, Mujaahid and other scholars, and he has 
    committed thereby a lesser form of kufr, wrongdoing and evil, but it is not 
    major kufr. This is the view of Ahl al-Sunnah wa’l-Jamaa’ah. Allaah says 
    (interpretation of the meaning): 

    “And 
    so judge (you O Muhammad 
    
    صلى الله عليه وسلم) 
    among them by what Allaah has revealed”

    [al-Maa’idah 5:49] 

    “And whosoever does not judge by what Allaah has revealed, 
    such are the Kaafiroon (i.e. disbelievers — of a lesser degree as they do 
    not act on Allaah’s Laws)”

    [al-Maa’idah 5:44] 

    “And whosoever does not judge by that which Allaah has 
    revealed, such are the Zaalimoon (polytheists and wrongdoers — of a lesser 
    degree)”

    [al-Maa’idah 5:45] 

    “And whosoever does not judge by what Allaah has revealed 
    (then) such (people) are the Fâsiqûn [the rebellious i.e. disobedient (of a 
    lesser degree)] to Allaah”

    [al-Maa’idah 5:47] 

    “But no, by your Lord, 
    they can have no 
    Faith, until they make you (O Muhammad 
    صلى 
    الله عليه وسلم) 
    judge in all disputes between them, 
    and find in themselves no resistance against your decisions, and accept 
    (them) with full submission”

    [al-Nisa’ 4:65] 

    “Do they then seek the judgement of (the days of) 
    Ignorance? And who is better in judgement than Allaah for a people who have 
    firm Faith”

    [al-Maa’idah 5:50]. 

    So the rule of Allaah is the best of rules, and it is the one 
    that must be followed; in it are the best interests of the ummah and its 
    happiness in this world and in the Hereafter, and the best interests of the 
    entire world, but most people are unaware of that. Allaah is the One Whose 
    help we seek, and there is no power and no strength except with Allaah, the 
    Most High, the Most Great. End quote. 

    Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz.