Numbers 13:19

13:19 and whether the land they live in is good or bad, and whether the cities they inhabit are like camps or fortified cities,

Numbers 32:17

32:17 but we will maintain ourselves in armed readiness and go before the Israelites until whenever we have brought them to their place. Our descendants will be living in fortified towns as a protection against the inhabitants of the land.

Numbers 33:55

33:55 But if you do not drive out the inhabitants of the land before you, then those whom you allow to remain will be irritants in your eyes and thorns in your side, and will cause you trouble in the land where you will be living.