Mosiah 9 – 10
I’m trying to figure out what really happened with Zeniff. I really don’t think that Mosiah would have sent an army to destroy the Lamanites as he had just left rather than fight and be destroyed (at the instruction of the Lord). I also doubt that he would have allowed a group to go if that was their expressed purpose. My best guess is that the leader who ordered Zeniff killed when he desired to spare the Lamanites decided that with the added strength that could be gathered from among the people of Zerahemla he would be able to destroy that Lamanites so he gathered the army he wanted and asked for declared that they were going to re-settle the land of their inheritance. Mosiah may have felt that he could not stop them – perhaps he was aware that they meant to fight their way into the land. Zeniff tripped up the plan (which would probably have failed anyway) when he argued that they could/should make a treaty with the Lamanites.
The world would be so much happier if all people would cease to blame the children of their enemies for the sins and grievances between their ancestors and instead judge and treat each new generation on their own terms – of course it would also help if hatred were not passed from generation to generation through the teaching of hateful half-truths (and they are almost always only half true).