The writer probably included this incident in the text because it resulted in a further definition of the laws governing inheritance in the land in a common situation. It also shows the faith of these women. They believed God would bring them into the land. Furthermore it reveals the fairness and compassion of God in His provision for these women whose father had died in the wilderness.
Normally when a father died, his sons divided his property with the eldest receiving a double portion. Daughters did not receive an inheritance other than their dowry. The dowry was a substantial present their father gave them when they married. The term dowry also refers to a gift the groom gave to his father-in-law when he married his daughter.
Notice that after Moses heard the women's complaint he took their case to the Lord (v. 5). This is another mark of Moses' spiritual leadership.
God decreed that in Israel when a man had no sons his daughters would divide his property (v. 8). If he had neither sons nor daughters, the father's nearest relative would receive his inheritance (vv. 9-11). Later (ch. 36) the Lord placed a restriction on daughters who inherited their father's estate. They had to marry within their own tribe to keep the inheritance within that tribe as it would have remained if the father had had sons.
This passage is interesting because it shows how case law developed in Israel. When a situation not covered by existing laws arose, like this one, the people involved would go to Moses and the high priest who would inquire of God. God would reveal what the people should do. This revelation then became precedent for similar cases that might arise later.
