Komentaryong Sumisipi para sa Mga Bilang 32:18

וישב טפנו בערי המבצר, "while our children will dwell in the fortified cities." This comment had to appear here and not previously when the two tribes mentioned the building of cities for their children (and women). They wanted to make it plain that once they could feel reassured about the safety of their families they could volunteer to add another undertaking, i.e. not to return to their own families until all the other tribes had taken over their respective inheritance. The time frame under discussion was 14 years, 7 years of conquest and another seven years for the distribution of the various lands. The two tribes made it plain that unless they left their families in a condition which made it unnecessary for them to worry they would only be with the other tribes during the seven years of conquest. This was why the Torah inserted these words in the middle of this verse although the statement נחלץ חושים should really have been followed immediately by verse 18.

The consideration about these tribes remaining with the main body of the Israelite army until after the distribution of the land also explains something which otherwise appears as contradictory. On the one hand they had said they would join and bear arms (verse 18) until התנחל, the other tribes would inherit; on the other hand they said in the earlier verse that they would participate until הביאותם אל מקומם, "until we have brought them to their place." If you accept our interpretation both statements make sense and are in place.

צדקת ה' עשה, “he carried out G’d’s judgments;” by honouring his verbal undertakings to Moses the tribe of Gad carried out G’d’s judgment. He (and the tribe of Reuven and half the tribe of Menasheh) had vowed not to return home until all the tribes had received their heritage.

והיצא מפיכם תעשו AND DO THAT WHICH HATH GONE OUT FROM YOUR MOUTH, as a vow to the Most High God (cf. Numbers 30:3), because you have taken it upon yourselves to pass over for war until the end of the subjugation and division of the land; — for Moses asked of them only, (v. 22): “Let [the land] be subdued and afterwards ye may return”, but they undertook, (v. 18): “[we will not return to our houses] until [the children of Israel] have inherited”, so you see that they made an additional promise, to stay on the western side the seven years during which they were dividing the land. And so, indeed, they did (cf. Joshua XXII.).