?Vayomru Bnei Gad u?Venei Re?uven?. Why does the Torah reverse the order from "B'nei Reuven u'Benei Gad" in the previous Pasuk ?
Ramban, R. Bachye #1 and Moshav Zekenim: Because, although Reuven was the son of one of Ya?akov?s main wives, Gad was the one to put forward the proposition and who subsequently became the spokesman for the tribes involved, as well as being the strongest. 1
Oznayim la'Torah: Because basically, the Torah always gives precedence to Reuven, who was the B'chor and the son of one of Ya'akov's main wives - Le'ah, whereas Gad, was the son of the maidservant - Zilpah. And the Pasuk mentions Gad first for the remainder of the Parshah, because they were the ones who were most interested in inheriting in Eiver ha'Yarden and who subsequently pushed for it, and Reuven only followed suite. 4
See Ba?al ha?Turim . See also Oznayim la'Torah, who cites many examples from Seifer Yehoshua.
See Devarim 33:2.
R. Bachye: Unafraid in spite of their living far from the other tribes in Eretz Yisrael.
See Oznayim la'Torah, who gives three reasons as to why Reuven were not as keen as Gad to receive their portion in Eiver ha'Yarden: 1. Because of the dnager posed by the neighboring nations of whom the mighty Gad ("ke'Lavi Shachein Vetaraf Zero'a Af Kodkod" - Ve'Zos ha'Berachah Devarim, 33:20) was not afraid; 2. Because Gad's flock's were far in excess of that of Reuven (See Oznayim la'Torah) and their need for good pasture was more acute than that of Reuven: 3. Because, because, by receiving their portion in Eiver ha'Yarden before the rest of the tribes, they would not receive a double portion in Eretz Yisrael - See Oznayim la'Torah.
?Vayomru B?nei Gad u?Venei Re?uven Vayomru el Moshe ? ?. What were the repercussion of asking for an inheritance that was initially destined for them?
R. Bachye (citing the Tanchuma and Midrash Rabah): Wealth that one takes for oneself that is not Heaven-sent cannot last, 1 as it is not subject to Hashem?s blessing (indeed, Reuven And Gad were the first to go into exile at the hand of Sancheriv)- in the same way as Korach and Haman, who took for themselves wealth that was not meant fo them and who lost everything.
Moreover, they displayed warped priorities - by choosing good grazing-grounds above living in Eretz Yisrael, which is holy territory. See R. Bachye who elaborates,


