Peter failed to walk on Galilee because he allowed the waves to break over him and swamp the power of his faith. Doubts and fears should never be cherished or hidden. Our eyes should be taken off ourselves. They should be removed from our own weakness and allowed to rest totally on God's strength. This is the divine prescription for securing the peace which passes all understanding and keeps the heart and mind in quietness and peace.
Faith needs to be cultivated.
Faith is increased by exercise, by being put to use. It is nourished by painful trials. Faith grows by reading and meditating upon the Word of God. Faith thrives in an atmosphere of prayer. Faith starts prayer to work.