Allāh says:

أَلَمْ تَرَ إِلَى الَّذِينَ يَزْعُمُونَ أَنَّهُمْ آمَنُوا بِمَا أُنزِلَ إِلَيْكَ وَمَا أُنزِلَ مِن قَبْلِكَ يُرِيدُونَ أَن يَتَحَاكَمُوا إِلَى الطَّاغُوتِ وَقَدْ أُمِرُوا أَن يَكْفُرُوا بِهِ وَيُرِيدُ الشَّيْطَانُ أَن يُضِلَّهُمْ ضَلَالًا بَعِيدًا ‎﴿٦٠﴾‏ وَإِذَا قِيلَ لَهُمْ تَعَالَوْا إِلَىٰ مَا أَنزَلَ اللَّهُ وَإِلَى الرَّسُولِ رَأَيْتَ الْمُنَافِقِينَ يَصُدُّونَ عَنكَ صُدُودًا ‎﴿٦١﴾‏ فَكَيْفَ إِذَا أَصَابَتْهُم مُّصِيبَةٌ بِمَا قَدَّمَتْ أَيْدِيهِمْ ثُمَّ جَاءُوكَ يَحْلِفُونَ بِاللَّهِ إِنْ أَرَدْنَا إِلَّا إِحْسَانًا وَتَوْفِيقًا ‎﴿٦٢﴾‏ أُولَٰئِكَ الَّذِينَ يَعْلَمُ اللَّهُ مَا فِي قُلُوبِهِمْ فَأَعْرِضْ عَنْهُمْ وَعِظْهُمْ وَقُل لَّهُمْ فِي أَنفُسِهِمْ قَوْلًا بَلِيغًا ‎﴿٦٣﴾‏

‘Have you not seen those who claim to have believed in what was revealed to you, [O Muḥammad], and what was revealed before you? They wish to refer legislation to ṭāghūt, while they were commanded to reject it; and Satan wishes to lead them far astray. And when it is said to them, “Come to what Allāh has revealed and come to the Messenger,” you see the hypocrites turning away from you in aversion. So how [will it be] when disaster strikes them because of what their hands have put forth and then they come to you swearing by Allāh, “We intended nothing but good conduct and accommodation.” Those are the ones of whom Allāh knows what is in their hearts, so turn away from them, but admonish them and speak to them a far-reaching word.’
[Al-Nisāʾ, 4:60-63].

Imām Ibn Al-Qayyim [d. 751 AH] said:
[Allāh] has related to us that whoever accepts the judgement, or judges himself by other than what was brought by the Messenger [of Allāh] [ﷺ] has indeed judged by ṭāghūt or has accepted it as a judiciary. ṭāghūṭ is any act of worship, subservience, or obedience a slave [of Allāh] takes part in that exceeds the boundaries [set by Allāh for him].

Thus, the ṭāghūt of any people is actualised whenever judgement is sought by them from other than Allāh and his Messenger [ﷺ], or they worship others besides Allāh, or they obey the commandments of others without knowledge from Allāh [of these commandments being in accordance with Allah’s commands], or they follow other than them in a state of ignorance concerning whether their actions are considered acts of obedience to Allāh. Such are the ṭāghūt of this world.

If you were to contemplate them and the conditions of mankind in relation to them, you will find that most of them are taken by those who oppose the worship of Allāh and call people towards the worship of these ṭāhgūt. They call away from adoption of the judgements of Allāh and His Messenger [ﷺ] towards the judgement of ṭāghūt; away from obedience and subservience to the Messenger [ﷺ] to the obedience and subservience of ṭāghūt. Those people have not taken the successful path of the saved from among this ummah – the ṣaḥābah and those who follow them. Neither do they hold the same intentions as them. Rather, they oppose them in methodology and execution. Then, the Most High relates to us concerning them that if it is said to them: Come to what Allāh has revealed and to the Messenger, they vehemently oppose this, refusing to answer the caller, and find pleasure in seeking the judgement of anyone other than them [Allāh and His messenger]. Then, Allāh threatens them with a catastrophe that will afflict them in their minds, or religion, or sight, or body, or wealth due to their obstinate rejection of what has been brought by the Messenger [ﷺ] and their taking other than him as a judge from whom them they seek and accept rulings, as the Most High says:

فَإِن تَوَلَّوْا فَاعْلَمْ أَنَّمَا يُرِيدُ اللَّهُ أَن يُصِيبَهُم بِبَعْضِ ذُنُوبِهِمْ ۗ ‎﴿٤٩﴾‏

‘And if they turn away – then know that Allah only intends to afflict them with some of their [own] sins.’
[Al-Māʾidah, 5:49].

They excuse themselves claiming they intended nothing but good conduct and accommodation; that is, by carrying out that which is pleasing to both parties. They allege the seeking of agreeableness, like the one who seeks to commensurate between what has been revealed to the Messenger [ﷺ] and those who contradict him. They allege that in doing so they are good-doers, intending only prosperity and accommodation. True imān stipulates none other than the raising of unadulterated opposition between that which has been brought by the Messenger [ﷺ] and anything that conflicts with him, be it a path, or way of being, or creed, or policy, or opinion. Pure īmān exists only in this opposition, not in seeking commensuration between the two. And Allāh alone is the One sought for guidance.

Source: Iʿlām Al-Muwaqqiʿīn 2:92-93
Translated by: Riyāḍ Al-Kanadī