במדבר, פרק ל״ו, פסוק ט׳

The division of the land of Israel was designed to preserve the unique identity of each tribe and prevent their territories from mixing. There is a profound connection between the people and their land. Each tribe was meant to fully integrate with its specific allocated region because every territory perfectly matched the character and national purpose of the tribe residing there [רש"ר הירש].

To ensure these boundaries remained intact, the restriction against transferring land from one tribe to another is stated multiple times. This repetition elevates the instruction from mere good advice to an absolute obligation binding upon all the Israelites [אור החיים]. Additionally, the repeated warning addresses the various ways property might change hands, strictly forbidding land transfers whether they occur through marriage, a husband's inheritance, or a son's inheritance [תורה תמימה, בכור שור].

The primary approach among commentators is that this strict prohibition was not a permanent law for all history, but rather a temporary Commandment for the generation first entering the land. The goal was to firmly establish the initial borders so every tribe would clearly know its exact territory. In subsequent generations, there was no real concern that land would shift between tribes. People naturally clung to their ancestral soil and had no desire to leave. If someone did inherit property in another tribe's region, it was largely useless to them, and they would typically sell it at a low price to the local residents. This practical reality naturally encouraged individuals to marry within their own tribe, preventing the transfer of estates without the need for an ongoing decree [מלבי"ם].

Even within this framework, the specific circumstances of the inheritance mattered. The restriction on transferring an estate applied specifically to a daughter who inherited her father's land; she had to marry within his tribe so the property would not be lost to another group. However, if a woman inherited land from her mother who belonged to a different tribe, that property had already effectively transferred into the father's family. In this scenario, the daughter was permitted to marry a man from her father's tribe, and the land would remain in her hands even though it was geographically located within the borders of a completely different tribe [העמק דבר].