Helaman 1:28

But when Moronihah had discovered this, he immediately sent forth Lehi with an army round about to head them, before they should come to the land Bountiful:

When Moronihah learned this, he quickly sent Lehi with an army. He sent them around to get ahead of the Lamanites before they could reach Bountiful.

When Moronihah realized what was happening, he immediately sent Lehi with an army to circle around and cut them off before they reached Bountiful.