This sidra begins with discussing the laws of verbal vows. A person who obligates themselves with a vow is required to fulfill it. Under certain circumstances, a husband or father can annul vows made by his wife or daughter.
The Israelites were commanded to take revenge on the Midianites for their part in causing Jewish men to sin (described in the end of the Torah reading of Balak). An army of 12,000 Israelites, led by Pinchas, waged battle against Midian. All adult Midianite males were killed, along with Bilaam and Midian’s five kings. The women, children, and battle spoils were brought back to the Israelite encampment.
Moshe was enraged that the Midianite females were spared, “They were the primary culprits; the ones who seduced the Israelites and brought about the plague which killed so many!” All women who had been involved in the campaign of seduction were killed. The soldiers were then instructed on how to purify themselves from the spiritual impurity (tumah) they contracted from contact with dead bodies in battle. They were also told how to kasher the food utensils which were among the spoils.
The spoils of the war were divided evenly between the soldiers and the greater community. From the portion of the spoils given to the soldiers, a tithe of 1/500th was given to Elazar the Kohen Gadol.
From the other portion of the spoils, the half divided amongst the rest of the Israelites, 1/50th was given to the Levites. The army officers counted the men who returned from battle, and determined that not a single soldier was killed. To show gratitude to God for this miracle, the soldiers donated all the gold jewellery, which they won from the Midianites, to the Mishkan (Tabernacle).
The tribes of Reuben and Gad owned lots of cattle. Seeing that the eastern bank of the Jordan — the lands of Sichon and Og which they had just conquered — had abundant pasture, they asked Moshe if they could settle there instead of Israel. Moshe accused them of following in the footsteps of the spies who were fearful of entering the Land and discouraged the entire nation from doing so. The Reubenites and Gaddites responded that they would leave their cattle and families behind in fortified cities, and all their men would enter Israel with their brethren and lead them in the conquest of the land. Only after all the land had been conquered and settled would they return to the other side of the Jordan.
Moshe accepted the offer, and informed Yehoshua and Elazar of the agreement. These two tribes, along with half of the tribe of Menashe settled on the eastern bank of the Jordan.