Alma 52:5

And now Teancum saw that the Lamanites were determined to maintain those cities which they had taken, and those parts of the land which they had obtained possession of; and also seeing the enormity of their number, Teancum thought it was not expedient that he should attempt to attack them in their forts;

Teancum saw that the Lamanites wanted to keep those cities and the land they had taken. He also saw how many of them there were. Teancum thought it was not wise to attack them in their forts.

Teancum realized the Lamanites were determined to keep the cities and territory they’d seized. And when he saw how massive their army was, he decided attacking their fortifications would be a mistake.