Alma 58:15

And it came to pass that when they saw that we were not strong, according to our numhers, and fearing that we should cut them off from their support, except they should come out to battle against us, and kill us, and also supposing that they could easily destroy us with their numerous hosts, therefore they began to make preparations to come out against us to battle.

When they saw that we did not have many soldiers, they got worried. They were afraid we would cut them off from their supplies. So they thought they needed to come out and fight us and kill us. They thought they could easily destroy us because they had so many soldiers. So they got ready to come out and fight us.

When they saw our numbers were small, they got worried. They feared we’d cut off their supply lines unless they came out and crushed us quickly. Confident in their overwhelming numbers, they started preparing for battle.