The fisherman is telling the bishop about the three hermits that live secluded on an island. The bishop believes how they live their life is the wrong way so he tells the fisherman to go to the island so he could talk to them.
This is what the three hermits look like, going from shortest to tallest. They all believe that living in solitude is there religion and their connection with God. The bishop looks at them through a telescope
The bishop gets to the island and tells the hermits to their face that how they're living is the wrong way. So he shows them the right way and makes them repeat the prayer after him and makes them practice it. They all had a little trouble speaking the prayer.
The bishop did not leave their island until they got the prayer right. He kept repeating it over and over again until it stuck. The hermits told the bishop they didn't know how to serve God, they only know how to support and serve themselves.
It started to get dark. The bishop literally made them change their ways. He headed off back to the vessel as the hermits were bowing too him.
As the bishop leaves he can hear them repeating the prayer which makes him feel accomplished. It wasn't the bishops job to make the hermits change their ways. They are on that island for a reason and it has nothing to do with the bishop.