Alma 48:23

Now they were sorry to take up arms against the Lamanites, because they did not delight in the shedding of blood; yea, and this was not all; they were sorry to be the means of sending so many of their brethren out of this world into an eternal world, unprepared to meet their God;

They were sad to pick up weapons against the Lamanites. They did not like killing. That was not all. They were sad to send so many of their brothers out of this world into the next world. These people were not ready to meet God.

They hated taking up arms against the Lamanites because they found no pleasure in bloodshed. More than that, they were grieved to be the ones sending so many of their brothers into eternity unprepared to meet their God.