וַיֹּ֣אמֶר מֹשֶׁ֔ה לִבְנֵי־גָ֖ד וְלִבְנֵ֣י רְאוּבֵ֑ן הַאַֽחֵיכֶ֗ם יָבֹ֙אוּ֙ לַמִּלְחָמָ֔ה וְאַתֶּ֖ם תֵּ֥שְׁבוּ פֹֽה׃
Lalu Musa berkata kepada bani Gad dan bani Ruben: “Apakah saudara-saudaramu akan pergi berperang, sedangkan kamu tinggal di sini?
Rabbeinu Bahya
The Midrash (Shabbat 89) says that Satan had brought darkness and confusion on to the globe at that time, and that he showed the Israelites an image of Moses lying on a bier. This accounted for the people saying: “arise let us make gods who will go before us, for this man Moses who brought us out from Egypt-we do not know what became of him.”
Moses had spoken of 40 whole days not including the day on which he ascended the mountain. Accordingly, the people should not have expected him before the 17th of Tammuz. When the Torah writes (verse 6): “they rose early in the morning,” this was the 17th of Tammuz. It was ממחרת, “on the day after the 16th of Tammuz.” On that day they offered sacrifices to the golden calf. At noon on that day Moses returned and smashed the Tablets. On the day after that, the eighteenth of Tammuz, he burned the golden calf and convicted the people who had actively participated in the cult of the golden calf and commanded the Levites to execute these people. On the nineteenth of the month he ascended the mountain again pleading for forgiveness for the people, remaining there another forty days. He spent the entire period in prayer and pleading with G’d as he himself testified in Deut. 9,25: ”the forty days during which I threw myself down, etc.” These days came to an end on the first day of Ellul. On that same day, after having briefly returned to the camp, Moses ascended the mountain again after having been invited to do so by G’d, (34,2) and remained for forty days. This was in preparation of receiving the second set of Tablets. These forty days came to an end on the Day of Atonement, the tenth day of Tishrei. On that day the sin of the golden calf was finally forgiven; on the day following the day of Atonement the people began bringing their contributions for the building of the Tabernacle. The Tabernacle was erected on the first day of Nissan following, i.e. close to a whole year after the Exodus. All of this teaches you that the sin of the golden calf preceded the matters described in Parshat Ki Tissa. [The instruction to make sockets for the Tabernacle from the half-shekel contributions which were to atone for that sin would not make sense if the Tabernacle had preceded the sin of the golden calf. Ed.] This is merely another example of the fact that the Torah did not see itself as obliged to report matters in chronological order (compare Tanchuma Ki Tissa 11).
Moses had spoken of 40 whole days not including the day on which he ascended the mountain. Accordingly, the people should not have expected him before the 17th of Tammuz. When the Torah writes (verse 6): “they rose early in the morning,” this was the 17th of Tammuz. It was ממחרת, “on the day after the 16th of Tammuz.” On that day they offered sacrifices to the golden calf. At noon on that day Moses returned and smashed the Tablets. On the day after that, the eighteenth of Tammuz, he burned the golden calf and convicted the people who had actively participated in the cult of the golden calf and commanded the Levites to execute these people. On the nineteenth of the month he ascended the mountain again pleading for forgiveness for the people, remaining there another forty days. He spent the entire period in prayer and pleading with G’d as he himself testified in Deut. 9,25: ”the forty days during which I threw myself down, etc.” These days came to an end on the first day of Ellul. On that same day, after having briefly returned to the camp, Moses ascended the mountain again after having been invited to do so by G’d, (34,2) and remained for forty days. This was in preparation of receiving the second set of Tablets. These forty days came to an end on the Day of Atonement, the tenth day of Tishrei. On that day the sin of the golden calf was finally forgiven; on the day following the day of Atonement the people began bringing their contributions for the building of the Tabernacle. The Tabernacle was erected on the first day of Nissan following, i.e. close to a whole year after the Exodus. All of this teaches you that the sin of the golden calf preceded the matters described in Parshat Ki Tissa. [The instruction to make sockets for the Tabernacle from the half-shekel contributions which were to atone for that sin would not make sense if the Tabernacle had preceded the sin of the golden calf. Ed.] This is merely another example of the fact that the Torah did not see itself as obliged to report matters in chronological order (compare Tanchuma Ki Tissa 11).
Ibn Ezra
The heads of the tribes: According to my opinion that this section is after the war with Midian, it is for this reason that [the section about that war] is after it; just as "And Miriam and Aaron spoke about Moses (Numbers 12:1) is after "and they were in Chatserot" (Numbers 11:35) [even though it happened earlier], as I explained.1 And Scripture states that the Children of Gad came to Moses and Elazar and the princes of the congregation and they spoke their words. And afterwards, it is written (Numbers 32:28), "Then Moses gave instructions concerning them to Elazar the priest, Joshua son of Nun, and the family heads of the Israelite tribes" - which are the princes of the congregation [just] mentioned. And since Moses said to the Children of Gad and the Children of Reuben (Numbers 32:24), "you shall do what comes out of your mouth"; it is therefore written (Numbers 30:2), "And Moses spoke to the heads of the tribes," and then (verse 3), "he shall do like everything that comes out of his mouth."
Or HaChaim
את כל אשר עשה, "all that He has done, etc." This statement incorporates the reason Moses insisted that the tribes of Reuven and Gad cross the river Jordan armed, ready to join the other tribes in the conquest of the West Bank. Moses says that G'd will do to the tribes on the West Bank what He had done to the Emorite Kings Sichon and Og. Just as G'd's help against those kings had been predicated on all of the tribes having readied themselves to do battle, so in order for G'd to do battle on behalf of the Israelites against the 31 kings on the West Bank, all the tribes had to be present in battle formation. In both instances it was G'd who did the actual fighting. In view of the above Moses was not able to say to Joshua "your own eyes have observed what G'd did to these two kings, etc." until after the two tribes had been commanded to cross the Jordan, etc. The collective merit of 12 tribes of Israel cannot be compared to the collective merit of 10 tribes. If G'd had been willing to fight on behalf of 12 tribes this was not proof that He would do the same on behalf of only 10 tribes. I have already explained this on Numbers 32,6.