Parshas Matos - Proper Role of Material Wealth
Parshas Matos contains three distinct themes: 1) Rules of shevuos and nedarim (vows and oaths); 2) the war against Midian and the disposition of all booty from that war; 3) granting the east bank of the Jordan to the tribes of Reuven, Gad and half of Menasheh. The latter two topics are somewhat connected, as they are both part of the overall military and settlement scenario. However, hilchos shevuos u'nedarim seems unrelated to either theme. Why are these halachos at the beginning of the parshah?
One cannot help but notice the stark contrast between the attitude of those who led the war against Midian and the leaders of the shevatim of Reuven and Gad, who requested settlement east of the Jordan. The war against Midian was referred to as a war for the sake of Hashem (31:3); booty which had been used by the Midianites for the preparation of food was ordered to kashered (ibid. v. 22-23); the troops purified themselves upon their return (ibid. v. 24); the military heads presented a portion of the goods to Moshe for Mishkan use, per Hashem's command, and they behaved in battle in a sanctified manner (ibid. 49-50 with Rashi on Shir Ha-Shirim 4:2). In contrast, the leaders of Shevet Reuven and Shevet Gad were criticized by Chazal for focusing on material wealth. (V. Rashi on 22:16, from Tanchuma.)
One gets the sense that the war against Midian represented the triumph of the spiritual over the physical and material (especially in light of the fact that the war was to avenge Midian's role in the orgy at Ba'al Pe'or, reflective of the depths of physical lust), and that settlement of the east bank was an economic plan, where material wealth was the primary factor.
Rashi (in Maseches Nedarim 2a) compares taking a neder to sanctifying the object of the neder, thereby placing the object off-limits. The prohibition of violating a neder (Bamidbar 30:3) is termed "Lo yachel", and Rashi (ibid.) quotes the Sifri which interprets the phrase as, "One should not make his words unsanctified ("chulin")."
Thus, the pivotal positioning of hilchos shevuos u'nedarim is to introduce the theme of proper use of material wealth. Material wealth can be utilized for holy purposes, such as in the war against Midian, or it can be exploited for its own sake. May we use our possessions in the spirit which God gave them to us.