Numbers 36:4 (KJV)

And they said, The Lord commanded my lord to give the land for an inheritance by lot to the children of Israel: and my lord was commanded by the Lord to give the inheritance of Zelophehad our brother unto his daughters.

And if they be married to any of the sons of the other tribes of the children of Israel, then shall their inheritance be taken from the inheritance of our fathers, and shall be put to the inheritance of the tribe whereunto they are received: so shall it be taken from the lot of our inheritance.

And when the jubile of the children of Israel shall be, then shall their inheritance be put unto the inheritance of the tribe whereunto they are received: so shall their inheritance be taken away from the inheritance of the tribe of our fathers.

And Moses commanded the children of Israel according to the word of the Lord, saying, The tribe of the sons of Joseph hath said well.

This is the thing which the Lord doth command concerning the daughters of Zelophehad, saying, Let them marry to whom they think best; only to the family of the tribe of their father shall they marry.