Believe the incredible and you can do the impossible. It is our want of faith that holds us back, even as Peter.  When did he begin to sink?  The Gospel gives us the reason. He took account of the winds, he began reading some surveys; it was established statistically that 99.44 percent of mankind cannot walk on water.  All of the incredulities were in the winds.  When he took his eyes off Christ, Peter began to sink.” Archbishop Fulton Sheen