BismilLaahir Rahmaanir Raheem.

Tribalism is a forbidden ideology that afflicts all human societies in every time period, originating in the worship of idols and reconstructing itself into many forms throughout the ages.

Allah has commanded us to uphold justice with all other human beings regardless of their race, religion, or identity. Allah says:
يَا أَيُّهَا الَّذِينَ آمَنُوا كُونُوا قَوَّامِينَ بِالْقِسْطِ شُهَدَاءَ لِلَّهِ وَلَوْ عَلَىٰ أَنفُسِكُمْ أَوِ الْوَالِدَيْنِ وَالْأَقْرَبِينَ إِن يَكُنْ غَنِيًّا أَوْ فَقِيرًا فَاللَّهُ أَوْلَىٰ بِهِمَا فَلَا تَتَّبِعُوا الْهَوَىٰ أَن تَعْدِلُوا
O you who believe, be persistently standing firm in justice as witnesses for Allah, even if it be against yourselves or parents and relatives. Whether one is rich or poor, Allah is more worthy of both. Follow not your desires, lest you not be just. Quran 4:135.

Tribalists, by contrast, reject universal standards of justice. They divide the world into the privileged in-group and the demonized out-groups, holding to the slogan “my people right or wrong.” Their love of their own people and hatred of different people causes them to rationalize and justify the unjustifiable. This wrong ideology is now even affecting marriages in Islam. As soon as you propose marriage to a brother or sister, the first question usually is "What tribe are you". If you mention his or her tribe then you hear maa shaa Allah, if not then it becomes in shaa Allah we will get back to you but that’s it SubhaanAllah. But please for our sisters in particular, never go into any marriage without your parents support please. Ensure you get their permission, support and blessings first. Obedience to parents is more important than marriage so ensure you use elders to get their support first else ignore the brother not your parents regardless of how good he is please.

Wathila ibn Al-Asqa’ reported: I said, “O Messenger of Allah, is it part of tribalism that a man loves his people?” The Prophet said:
لَا وَلَكِنْ مِنَ الْعَصَبِيَّةِ أَنْ يُعِينَ الرَّجُلُ قَوْمَهُ عَلَى الظُّلْمِ
No, rather it is tribalism that he supports his people in wrongdoing.
Sunan Ibn Majah 3949.

Love for one’s people is normal and healthy if it leads to good deeds, but such love that comes at the expense of justice is no true love at all. Tribalism by this definition has been rejected by Islam in the harshest terms. Tribalism is a form of “blind following” whose adherents live in “ignorance,” an allusion to the pre-Islamic worship of idols.

Jundab ibn Abdullah reported: The Messenger of Allah, peace and blessings be upon him, said:
مَنْ قُتِلَ تَحْتَ رَايَةٍ عِمِّيَّةٍ يَدْعُو عَصَبِيَّةً أَوْ يَنْصُرُ عَصَبِيَّةً فَقِتْلَةٌ جَاهِلِيَّةٌ
Whoever is killed under the banner of blind following, who calls to tribalism or supports tribalism, then he has died upon ignorance. Sahih Muslim 1850.

The Prophet disowned anyone who lives by the ideology of tribalism or supports it in any way. Tribalists might be outwardly Muslims, but in reality Allah will not count them among the true believers.

Jubair ibn Mut’im reported: The Messenger of Allah, peace and blessings be upon him, said:
لَيْسَ مِنَّا مَنْ دَعَا إِلَى عَصَبِيَّةٍ وَلَيْسَ مِنَّا مَنْ قَاتَلَ عَلَى عَصَبِيَّةٍ وَلَيْسَ مِنَّا مَنْ مَاتَ عَلَى عَصَبِيَّةٍ
He is not one of us who calls to tribalism. He is not one of us who fights for the sake of tribalism. He is not one of us who dies following the way of tribalism. Sunan Abu Dawud 5121.

May Allah keep guiding us all and protect us from any satanic influences. Aameen.