Ether 15:14

wherefore they were for the space of four years, gathering together the people, that they might get all which were upon the face of the land, and that they might receive all the strength which it were possible that they could receive.

So for four years they brought people together. They wanted to get everyone in the land. They wanted to get as strong as they could possibly be.

For four years they spent gathering people—trying to collect everyone they could find and amass every bit of strength possible.