Alma sought King Mosiah’s help in dealing with sinful beliefs and practices being spread among the people. Mosiah, however, could not involve the government in Church matters. Even though the beliefs of some people were evil, Nephite law allowed them to believe as they chose (see Alma 30:7–11). In this sense, the people had committed no crime.
As the head of the Church it was Alma’s responsibility to judge such people, so he turned to the Lord for instructions. Mosiah 26:15–32 contains the revelation of the Lord to Alma. The Lord explained the need to forgive the repentant and to excommunicate the rebellious in maintaining the good name of the Church. This stance was reaffirmed in our dispensation when the Lord revealed that the Church could not punish a member beyond excommunication for any sin or crime committed (see D&C 134:10).