What does Matthew 14:28 mean?

Peter, Matthew, and the other disciples are in a boat working their way very slowly across the Sea of Galilee (Matthew 14:22). A strong wind against them has created rough seas and forced them to row well into the night (Matthew 14:24). Their exhaustion turns to terror when they see a figure emerging from the darkness, on foot somehow, and approaching their boat by walking on waves (Matthew 14:25–26). Finally, Jesus says that it is Him and tells them not to be afraid (Matthew 14:27).

Peter's response is dramatic and would have been totally unexpected from any other person. Given Peter's impulsive nature, though, it's very much in his nature. He calls out to the figure on the water, asking that if it really is Jesus, He would command Peter to come to Him on the water. He seems to be testing the figure's identity by asking Him to let Peter walk on water, too.

While this seems like an odd way to establish that the person is really Jesus, it's not as bizarre as it may sound. Some scholars suggest that Peter's real meaning was not "if," as in "should it happen to be true," but as in "since it's you, let me come to you on the water." It helps to remember that Peter and the other disciples had already been sent out and had performed some of the same miracles that Jesus had done (Matthew 10:1).

Thanks to some combination of fear, faith, and impulse, Peter is willing to attempt to walk on water, himself, so long as he knows it's Christ giving him the command.