There is no change from Matthew 5:9.
In both Jesus’s Jerusalem and in the Nephite world, there was a context of conflict. For those in Jerusalem, it was with the Romans. In the Nephite world, it was traditionally with the Lamanites, but also within the Nephite people themselves. Those conflicts led to dissensions, and those wars and contentions were always dangerous.
In those conditions of conflict, Jesus is preaching conciliation and peaceful ways of living, rather than rising in rebellion, or initiating military actions on those with whom we might disagree.
When he indicates that “they shall be called the children of God,” he is indicating that this is the way to follow God’s commandments.