When therefore they had rowed about twenty-five or thirty stadia,{25 to 30 stadia is about 5 to 6 kilometers or about 3 to 4 miles} they saw Jesus walking on the sea, and drawing near to the boat; and they were afraid.
Jesus walking on the sea ... Moses, as God's servant, divided the sea; Jesus, as God's Son, walked upon it!  Of course, rationalism refuses to accept this, saying, "There was really no miracle; the disciples were mistaken; the Lord was only walking on the shore near the vessel; and the superstitious fear of the disciples made them think he was walking on the sea; and that they put ashore and took him on board, etc., etc."  Such views are impossible of reconciliation with the New Testament records of what happened.  Three New Testament writers recorded this miracle, John and Matthew having been eyewitnesses of it; and Mark was very close to Peter who also had witnessed it and even participated in it himself!  See parallel account in Matthew for this writer's comments on this miracle, Commentary on Matthew,  Matthew 14:13-36.