3 But if they are married to any of the sons of the other tribes of the people of Israel then their inheritance will be taken from the inheritance of our fathers, and added to the inheritance of the tribe to which they belong; so it will be taken away from the lot of our inheritance.

Matthew Henry's Commentary on Numbers 36:3

Commentary on Numbers 36:1-4

(Read Numbers 36:1-4)

The heads of the tribe of Manasseh represent the evil which might follow, if the daughters of Zelophehad should marry into any other tribes. They sought to preserve the Divine appointment of inheritances, and that contests and quarrels should not rise among those who should come afterwards. It is the wisdom and duty of those who have estates in the world, to settle them, and to dispose of them, so that no strife and contention may arise.