John Gill Commentary Numbers 36:9

"So shall no inheritance remove from one tribe to another tribe; for the tribes of the children of Israel shall cleave every one to his own inheritance." — Numbers 36:9 (ASV)

Neither shall the inheritance remove from one tribe to another ,
&c.] Which was one end of the year of jubilee, but that did not sufficiently secure it without this law, as this case shows:

but everyone of the tribes of Israel shall keep himself to his own
inheritance ;
the chief view of which was, that it might clearly appear of what tribe and family the Messiah sprang when he came.