He chose the best of the land for himself: that is, in the division of the land of Canaan among the twelve tribes. Another way to express this is “You chose the best of the land for yourselves.”

A commander’s portion: this means “a larger share,” which would be given to a leader.

And he came to the heads of the people: New Revised Standard Version has “he came at the head of the people.” However, Good News Translation and others follow the text of old translations and take the meaning as “the leaders of Israel” (see the Good News Translation footnote). This gives the sense that, when the tribal leaders came together to divide the land, they decided that the tribe of Gad should have “a ruler’s portion.”

Revised Standard Version indicates no textual problems here; New Jewish Publication Society’s Tanakh, however, notes that the meaning of the whole of verse 21 is uncertain. A change to the way the text of the first three lines is read is proposed by Hebrew Old Testament Text Project ({C} rating), resulting in the following: “He chose the best portion for himself, for (where) the portion of the commander (was) there the chiefs of the people gathered together.” In this restructured text the second line is joined to the third, not to the first. There seem to be as many solutions to this problem as there are translations.

Out of the many possibilities it is recommended that Revised English Bible serve as the basic text:

• He chose the best for himself,
for to him was allotted a ruler’s portion,
when the chiefs of the people were gathered together.

We may reorder the first three lines of the verse as follows:

• When the tribal leaders met together
they assigned the best of the land to you;
it was a ruler’s portion.

Revised Standard Version has reversed the order of the last two lines, translating with Israel he executed the commands and just decrees of the LORD. It is recommended that this rendition be ignored completely. New Revised Standard Version “he executed the justice of the LORD, and his ordinances for Israel” is better. For “ordinances” see 4.1.

The last two parallel lines may be translated as follows:

• When the leaders of Israel were gathered together,
he [Gad] carried out the LORD’s righteous will
and his ordinances [or, laws] for the people of Israel.

If translators choose to follow the radical restructuring of the first three lines of the verse suggested above, a possible model for the whole verse is:

• When the leaders of the tribes met together,
they assigned the best of the land to you—
the ruler’s portion.
You also carried out the LORD’s righteous will
and his ordinances for the people of Israel.

The following is offered as another possible model:

• He chose the best of the land for himself;
When the leaders of the tribes gathered together
They assigned a leader’s share to him.
He carried out the LORD’s righteous will,
He obeyed the laws that the LORD gave to the people of Israel.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .