[Division of Wilderness and Mountains]

Answer—and Allah is the One who grants success: The judge must decide between them according to what they have mutually recognized and according to the title-deeds (baṣāʾir) in their possession to that effect. We say this for several reasons:
1. Ruling otherwise would lead to rejection of the judgment, lack of acceptance of it, and accusing the judge of injustice, and the like.
2. What we have said does not contravene what has come from the Prophet (May Allah bless him and his family and grant them peace) that people share in that; for even though they share in it, there is no objection to the partners agreeing to divide what they share if division preserves them from dispute, disagreement, and strife. When they divide and consent, each side has relinquished what lies in the other side’s hand.
3. Apparently, scholars and judges have affirmed the tribes upon that.
Moreover, tribes do not dispute except over what special rights have been established for them—such as flowing watercourses to their fields, or a tribe’s wood-gathering ground and pasture. The title-deeds and documents in their hands typically record what was agreed between the tribes—that such-and-such a defined location is woodlot and pasture for the people of that quarter, and such-and-such a place is for the people of another quarter. In that case, the people of one quarter are partners in what has been designated for them, and the people of the other quarter are partners in what has been designated for them. Thus, the ḥadīth, “People are partners in three …,” is to be understood as: the people of each quarter are partners—not the entirety of humankind. Therefore, there is no explicit contradiction of what the Law has brought.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2