IN A NUTSHELL
Parashat Mattot begins with Moshe teaching the people about promises – vows and oaths – including how they should be kept and how they can be cancelled.
Two tribes, Reuven and Gad, together with half the tribe of Menashe, then ask permission to dwell on the east side of the River Jordan where the land is ideal pasture for their cattle. Moshe is disappointed that they are choosing to live outside of the land of Israel, but eventually he says yes, as long as they first join in all the battles for the Promised Land, west of the Jordan, helping the rest of the Israelites.
QUESTION TO PONDER
Why is Moshe disappointed by the request of these tribes and what might it have to do with the other subject of the parasha (vows and oaths)?