Alma 53:15

and Helaman feared lest by so doing, they should lose their souls; therefore all those which had entered into this covenant, were compelled to behold their brethren wade through their afflictions, in their dangerous circumstances, at this time.

Helaman was scared that if they broke their promise, they would lose their souls. So all those who made this promise had to watch their brothers go through hard times and danger.

Helaman was afraid that if they broke their promise, they’d lose their souls. So all those who had made this covenant were forced to stand by and watch their Nephite brothers wade through terrible suffering in a time of extreme danger.