What does Matthew 14:30 mean?
Peter walked on the water. When he realized it was Jesus walking toward the disciples' boat (Matthew 14:22–27), Peter wanted to do what Jesus was doing. He believed it was possible, and asked Jesus to tell him to get out of the boat and walk on the Sea of Galilee (Matthew 14:28–29). Peter, after all, had been sent by Jesus to do other miracles with Jesus' power and under Jesus' authority (Matthew 10:1). He'd helped to feed thousands of people with a tiny portion of bread and fish (Matthew 14:13–21). In Peter's mind, there was no reason he couldn't do this, as well, so long as Christ was the One making it happen.When Jesus said, "Come," Peter climbed over the side of the boat and walked on water. Aside from Jesus, no other person in human history had ever done such a thing—not even the greatest of Israel's prophets.
That moment of victory didn't last long, though. At some point between leaving the boat and making it to Jesus' side, Peter's human doubt seems to catch up with his enthusiastic faith. He suddenly notices the ferocious wind and the size of the waves it was driving up. Fear takes over his faith, and when you're trying to walk on water, there's no margin of error. Peter begins to sink, crying out to Jesus to save him.
It's essential to notice that Peter's total confidence in the power of Jesus allowed Him to walk on the water, as Jesus did. It was fear replacing confidence which caused him to sink.