RAV KOOK ON Chukat Part 1: The Book of God's Wars

The Torah reading concludes with an obscure reference to the “Book of God’s Wars,” describing the Arnon canyon near the border between the Land of Israel and Moab. The verses are cryptic, and the Talmud (Berachot 54a-b) fills in the details with the following story: Just before the Israelites were to enter the Land of Israel, the Amorites (one of the Canaanite nations) laid a trap for them. They chipped away at the rock, creating hiding places along a narrow pass in the Arnon canyon. There the Amorite soldiers hid, waiting for the Israelites to pass through, when they could attack them with great advantage.