Numbers 21

Here in this chapter we read first of Israel being attacked by the Canaanite ruler, king Arad, who took captives from Israel. But Israel, now, believing in God, defeated king Arad in their counter strike, as opposed to what happened many years before (Numbers 14:45) when they were defeated because of their unbelief.

Then we read again that the people, as they continued their journey, murmured and complained again against God and Moses. As punishment, God sent them fiery snakes and many died. The people cried out and sought for mercy, and so Moses was told by God to make a bronze serpent and set it on a pole that anyone who was bitten who would look at it would live.  

Israel then further journeyed, making various stopovers at certain places.

Then as they got to the border of Sihon, king of the Amorites, they sent messengers to him to ask permission that they, if he pleases, would pass through his territory. They promised that they won't take anything from his land. But Sihon reacted violently against Israel. But Israel defeated him and took possession of his territory.

As they continued their journey, Israel was met again by another opposition. Og, king of Bashan, came out against them. Emboldened by God's promise of victory, Israel fought and defeated Og. They then also took possession of his land.