The ironic juxtaposition is emphasized in the words Mormon chooses to describe this missionary effort. The Lamanites “did preach with exceedingly great power and authority.” This is no sham conversion to the gospel. These Lamanites are fully converted, and it would appear that they have been empowered with the priesthood.
Note the affect on the Nephites who were able to listen to their message. They were brought down “into the depths of humility.” They would have to be. All of their national pride would have taught them religious superiority over the Lamanites, and now they would have to admit that the Lamanites were righteous, and calling them to repentance. Only the humble could hear such a message. Paul must have faced such a challenge when he first began to preach. Having been a persecutor of the saints, he becomes one of their foremost teachers. Perhaps, however, this is also one of the reasons that Paul’s significant ministry was in the lands outside of Jerusalem, away from his former actions against the saints.