This excerpt is taken from Dr. Yusuf Al-Qaradawi's book Halal and Haram in Islam, translated into Urdu by Muhammad Tahir Naqqash.
Declaring halal as haram and haram as halal is a form of shirk:
Islam has strongly condemned those who assume the authority to declare things permissible or forbidden arbitrarily. Especially, it has severely criticized those who make lawful things unlawful, because as a result, a person unnecessarily undergoes hardship and difficulty, ultimately leading to a tendency towards extreme (violent) religiosity, whereas the Prophet Muhammad ﷺ strictly suppressed the tendency towards extremism and violence and severely condemned those who adopt such behavior. The Prophet ﷺ said:
ألا هلك المتنطعون، ألا هلك المتنطعون، ألا هلك المتنطعون
Be aware! Those who create extremism and violence in religion are destroyed. Be aware that those who create extremism and violence in religion are destroyed. Be aware! Those who create extremism and violence in religion are destroyed.
Reference: (Musnad Ahmad: 3861, Muslim, Book of Knowledge, Chapter on the Destruction of Extremists, Hadith: 2670, Abu Dawood, Book of Sunnah, Chapter on Adherence to the Sunnah, Hadith: 4608)
And he described the characteristic of the Muhammadan message ﷺ as:
بعثت بالحنيفية السمحة
I have been sent with a religion that is both upright (Hanif) and broad-minded.
Reference: (This narration is authentic or has no weakness according to Musnad Ahmad with differences in wording Musnad Ahmad ibn Hanbal: 1/236, Hadith No: 1207 - 6/116 Hadith No: 24855, Al-Adab Al-Mufrad by Bukhari, Hadith No: 287, Al-Mu'jam Al-Kabir by Al-Tabarani: 8/216, No: 7868, Silsilat al-Ahadith al-Sahihah by Albani, Hadith No: 188)
Thus, this religion is upright in matters of belief and monotheism and broad in matters of Shariah and actions. Acts like polytheism, disbelief, and making lawful things unlawful are completely opposite to it. In one hadith, the Prophet ﷺ said that Allah, the Blessed and Exalted, says:
إني خلقت عبادي حنفاء وإنهم أتتهم الشياطين فاجتالتهم عن دينهم وحرمت عليهم ما أحللت لهم وأمرتهم أن لا يشركوا بي ما لم أنزل به سلطانا
I created My servants on the upright religion, but the devils misled them and made unlawful for them what I had made lawful, and commanded them to associate partners with Me for which I have sent down no authority.
Reference: (Muslim, Book of Paradise, Chapter on the Attributes by which the People of Paradise are Known in this World, Hadith: 2865)
It is clear from this that making lawful things unlawful is akin to polytheism. Therefore, the Quran strongly rejected the Arab polytheists for their shirk (polytheism), idol worship, and for making pure things like crops and livestock unlawful for themselves. Bahirah, Sa'ibah, Wasilah, and Ham were the livestock they had forbidden. When a she-camel gave birth to five offspring and the last one was male, these polytheists would cut the ear of that she-camel and forbid riding it, leaving it for their idols. Then slaughtering it and carrying loads on it became unlawful, and it could not be taken to water or pasture. They named it Bahirah, meaning the she-camel with the cut ear.
Similarly, Sa'ibah was the name for a she-camel that a person would leave in the name of his idols upon returning from a journey or recovering from illness.
If a goat was female, they considered it their right, and if male, it belonged to their idols. If both male and female were born, they would free the male instead of slaughtering it for their idols and called it Wasilah. Likewise, when the offspring of a camel's child became capable of carrying loads, they forbade riding and carrying loads on that old camel and named it Ham. The Quran declared this prohibition as disobedience and sin and left no room for following the misguided ways of their ancestors, saying:
مَا جَعَلَ اللَّهُ مِنْ بَحِيرَةٍ وَلَا سَائِبَةٍ وَلَا وَصِيلَةٍ وَلَا حَامٍ ۙ وَلَٰكِنَّ الَّذِينَ كَفَرُوا يَفْتَرُونَ عَلَى اللَّهِ الْكَذِبَ ۖ وَأَكْثَرُهُمْ لَا يَعْقِلُونَ 103 وَإِذَا قِيلَ لَهُمْ تَعَالَوْا إِلَىٰ مَا أَنْزَلَ اللَّهُ وَإِلَى الرَّسُولِ قَالُوا حَسْبُنَا مَا وَجَدْنَا عَلَيْهِ آبَاءَنَا ۚ أَوَلَوْ كَانَ آبَاؤُهُمْ لَا يَعْلَمُونَ شَيْئًا وَلَا يَهْتَدُونَ
Allah has not appointed Bahirah, nor Sa'ibah, nor Wasilah, nor Ham. Those who disbelieve invent lies against Allah, and most of them are without understanding. When they are called to what Allah has revealed and to His Messenger, they say, "Sufficient for us is that upon which we found our forefathers." Even though their forefathers knew nothing and were not guided?
Reference: (Al-Ma'idah: 103-104)
In Surah Al-A'raf, while mentioning the original unlawful things, it says:
قُلْ مَنْ حَرَّمَ زِينَةَ اللَّهِ الَّتِي أَخْرَجَ لِعِبَادِهِ وَالطَّيِّبَاتِ مِنَ الرِّزْقِ
Say: Who has forbidden the adornment of Allah which He has produced for His servants and the good things of provision?
Reference: (Al-A'raf: 32)
قُلْ إِنَّمَا حَرَّمَ رَبِّيَ الْفَوَاحِشَ مَا ظَهَرَ مِنْهَا وَمَا بَطَنَ وَالْإِثْمَ وَالْبَغْيَ بِغَيْرِ الْحَقِّ ۖ وَأَنْ تُشْرِكُوا بِاللَّهِ مَا لَمْ يُنَزِّلْ بِهِ سُلْطَانًا وَأَنْ تَقُولُوا عَلَى اللَّهِ مَا لَا تَعْلَمُونَ
Say: My Lord has only forbidden immoral deeds, whether open or secret, sin, unjust aggression, and associating with Allah that for which He has sent down no authority, and saying about Allah that which you do not know.
Reference: (Al-A'raf: 33)
This discussion of permissibility and prohibition appears in the Meccan Surahs, which is evidence that in the view of the Quran, this issue is not about minor details but about principles and generalities.
In Medina, some Muslims developed extremism and a tendency to forbid pure things for themselves. At that time, Allah revealed decisive verses guiding them to remain within the limits set by Allah and on the straight path:
يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تُحَرِّمُوا طَيِّبَاتِ مَا أَحَلَّ اللَّهُ لَكُمْ وَلَا تَعْتَدُوا ۚ إِنَّ اللَّهَ لَا يُحِبُّ الْمُعْتَدِينَ 87 وَكُلُوا مِمَّا رَزَقَكُمُ اللَّهُ حَلَالًا طَيِّبًا ۚ وَاتَّقُوا اللَّهَ الَّذِي أَنْتُمْ بِهِ مُؤْمِنُونَ
O you who have believed! Do not forbid the good things which Allah has made lawful for you, and do not transgress. Indeed, Allah does not like transgressors. Eat of the lawful and good provisions which Allah has provided for you, and fear Allah, in whom you are believers.
Reference: (Al-Ma'idah: 87-88)