Is it permissible to fight a tribe that threatens to kill anyone from our tribe because we refused to hand over the killer or his family to them?

A Muslim's life and interactions with people must be based on Islamic law, not tribal loyalties or pre-Islamic customs, as these lead to disunity and dispersion. It is advisable to spread knowledge among tribes, for ignorance leads to hateful actions. If murder necessitates retribution (Qisas), then the victim's family has the right to demand it, or blood money (Diyah), or forgiveness. The implementation of Hudud (punishments) is the responsibility of the ruler, not the general public. The victim's family has no right to demand that you boycott the killer's family, nor are they permitted to kill anyone among you unjustly. If they attack you, it is lawful for you to defend yourselves. To solve the problem, it is advisable to delegate sensible individuals from both tribes or to refer the matter to the responsible authorities.