What does Matthew 14:29 mean?
This section of Matthew 14 is full of unexpected events. First, Jesus shows up walking on the water in the middle of the Sea of Galilee. This is in the very early hours of the morning after the disciples have been rowing against a rough wind all night long. They believe Jesus to be a ghost until He speaks and identifies Himself. Peter, apparently convinced, has asked Jesus to command him to come out to Him and walk on the water, too (Matthew 14:22–28).On the one hand, Peter's request shows great faith in God's power and great enthusiasm to participate with Jesus in this exciting moment. His response to a chaotic moment is to declare his confidence that Christ will grant the power to do anything Christ commands. That's very much in keeping with the miracle these men have recently witnessed (Matthew 14:13–21), as well as those Jesus empowered them to perform earlier (Matthew 10:1).
Jesus grants Peter's request. He says, simply, "Come." Amazingly, Peter comes. He climbs out of the boat and does not immediately fall through the water. He really, truly walks on the water, as Jesus had been doing. He does the impossible by the power of God. Just as an "unachievable" task of feeding thousands was accomplished through obedience, Peter does what should be hopelessly ridiculous by following the commands of Jesus.
On the other hand, Peter's impulsive faith is subject to impulsive doubts, nearly resulting in disaster (Matthew 14:30).