Alma 1:19

But it came to pass that whosoever did not belong to the Church of God, began to persecute those that did belong to the Church of God, and had taken upon them the name of Christ;

But people who did not belong to God’s church started to treat badly those who did belong to God’s church and had taken Christ’s name.

But those outside God’s church began persecuting believers—those who’d taken Christ’s name.