Mosiah 21:6

And it came to pass that the people began to murmur with the king, because of their afflictions; and they began to be desirous to go against them to battle. And they did afflict the king sorely with their complaints; therefore he granted unto them that they should do according to their desires.

The people began to complain to the king because of their troubles. They wanted to fight against the Lamanites. They bothered the king so much with their complaints that he let them do what they wanted.

The people began complaining to the king about their suffering, demanding to fight back. They pressured him relentlessly until he finally gave in and let them do what they wanted.