The parsha of Mattos opens with a discussion of the laws of vows and oaths. The Torah impresses upon us to take our words seriously and not fall victim to the "talk is cheap" mentality.

The Torah then describes the Jewish people's battle against Midian and their eventual victory. Before the Jews cross into the Land of Israel, the tribes of Reuben and Gad request permission to settle on the east side of the Jordan River where it is more suitable for their abundant livestock. Moses, initially opposed to the idea, asks G-d for permission for them to live there.  G-d consents on the condition that they assist in conquering the entire Land of Israel before settling in their own area. This process takes 14 years.