The Herod talked about here is the son of Herod who killed the boys in chapter 2. Herod convinced Herodius to divorce his brother, Philip, and marry him instead. John had criticized them for doing this and was put in prison. Herodius gets her revenge by manipulating Herod into beheading John. Herod must have had a guilty conscience because, when he hears about Jesus, he thinks John the Baptist has come back to life. Jesus performed a couple of amazing miracles by feeding 5000 people with a small lunch and by walking on water. Peter had an amazing experience despite his wavering faith. He has enough faith to get out of the boat, but not enough to stay on top of the water.
We see a couple of examples of responses to Jesus’ miracles. Herod was aware of Jesus’ miracles, but does nothing to become one of his followers. Herod seems to react more in fear. Peter’s response is to be a follower, but a somewhat unreliable one. Obviously, we are better off being an unreliable follower than one who rejects Jesus altogether. Peter’s faith, like ours, will have a chance to grow as he has more experiences with Jesus.