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