What Peter did was admirable; it was also highly characteristic of him – he was very forward in all his responses. He heard the words, ‘It is I’, and he wanted to respond in the clearest possible way.
Mark doesn't mention Peter’s attempt to go to Christ, walking on the water, and the question is often asked, why does he leave it out? There are various answers given. One answer for example is, ‘We know that Mark’s Gospel is really Peter’s own Gospel. Mark was the penman, the secretary, but Peter is behind it’, which is true, and therefore Peter is presumed to be too modest to mention his own encounter of walking on the water. But surely the explanation is quite simple. Mark’s Gospel was intended to be an evangelistic tract, and had an entirely evangelistic intent. It passes over a number of things that are not directly linked to its evangelistic purpose, and it takes the reader from miracle to miracle, from wonder to wonder, and from one event to another that directly address the evangelistic purpose of the Gospel. This event involving Peter is first of all a lesson about faith, for believers.