Jehovah reinforces the nature of this new covenant associated with the church. As the entry into the church, baptism takes on a new and more important role. It continues to represent repentance, but it also represents belonging to the community which accepts Jehovah’s reiterated covenant.
Those who enter the church and are repentant accept the atoning mission of the Messiah. That is the essential aspect of what Abinadi preached, and which Alma has reinforced. This is a church that looks forward explicitly to the coming Messiah more than back on the law of Moses, even though they still fall under, and obey, that law.
Because they are known by Jehovah’s name, and are His, they will know Him in the resurrection, and they will receive their just reward in the next world.