John Gill Commentary Numbers 36

And the chief fathers of the families of the children of
Gilead
The princes, as Aben Ezra; so the Septuagint version, which was the tribe of Manasseh, whose grandson Gilead was, as follows:

the son of Machir, the son of Manasseh of the families of the sons of
Joseph, came near ;
to the house of judgment, as the Targum of Jonathan, the sanhedrim or court of judicature, consisting of the following persons:

and spoke before Moses ;
the Septuagint version adds, "and before Eleazar the priest", as in (Numbers 27:2) (32:2)

and before the princes, the chief fathers of the children of Israel :
the princes of the several tribes; or it may be rather the seventy elders.

And they said
One in the name of the rest:

the Lord commanded my lord ;
that is, Moses, whom they address in a very respectable manner, being the chief governor of the nation under God:

to give the land for an inheritance by lot to the children of Israel ;
which command may be seen, in (Numbers 26:53–56) :

and my lord was commanded by the Lord to give the inheritance of
Zelophehad our brother ;
or kinsman, being of the same tribe:

unto his daughters ;
who sued for it, and upon Moses's consulting the Lord about it, it was ordered they should have it, (Numbers 27:1–11) and which these princes observed was likely to be attended with the following inconvenience.

And if they be married to any of the sons of the other tribes
of the children of Israel
Which was not an unreasonable supposition, and perhaps was judged very probable and likely, if some method was not taken to prevent it; which they might conclude from the application of some young men of the other tribes unto them:

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 ;
for the inheritance given unto them would of course, the above being the case, descend to their sons, and whose fathers being of other tribes, it would be fixed there:

so shall it be taken from the lot of our inheritance ;
which gave them some concern; for though this was no personal injury to them, nor any detriment to their families and estates, yet, as it was a lessening of their tribe, they were uneasy at it; and the rather they might be, since half their tribe was to settle on that side Jordan, where they now were:

and now all this, the suit of the daughters of Zelophehad for their father's inheritance, which was granted them, the address of young men to them as heiresses, the concern of the heads of the tribe of Manasseh on this account; all this, I say, being before they entered into the land, or it was conquered by them, or divided to them by inheritance, show their strong faith and assurance that they should possess it.

And when the jubilee of the children of Israel shall be
At which time inheritances were to be restored to the original proprietors of them; yet this would be of no service in the present case, but rather the contrary, since it would fix the inheritances of these daughters in another tribe or in other tribes into which they should marry; and so Aben Ezra and Jarchi interpret it, "though" there shall be a jubilee, that will be of no advantage; it will not remedy this inconvenience: for

then shall their inheritance be put unto the inheritance of the tribe
whereunto they are received ;
it being one principal part of the business of the jubilee year to settle the inheritances of every tribe; and these daughters being married into another tribe, of consequence their inheritance would be placed there; or should it be sold by their husbands, or their sons, at the year of jubilee it would be restored to them as of such a tribe:

so shall their inheritance be taken away from the inheritance of the
tribe of our fathers ;
and thereby be a lessening of it; and every tribe being ambitious of preserving and increasing its grandeur, this affair sensibly affected the heads of this tribe.

And Moses commanded the children of Israel
Even all the tribes of Israel, whom the following law concerned, as well as the tribe of Manasseh:

according to the word of the Lord ;
whom no doubt he consulted on this occasion, as he did when the daughters of Zelophehad applied to him about the inheritance of their father:

saying, the tribe of the sons of Joseph has said well ;
in showing such a concern for the welfare of their tribe; the consideration of which would be of service to them all, and therefore was worthy of notice. Aben Ezra observes, that the heads of the fathers spoke for the sake of every tribe, what was for the good of them all, and therefore was well spoken.