As long as Peter was holding on to the word of Jesus ‘come’ he was walking on water. But the moment Peter forgot about the word Jesus gave him to come towards him, and began to trust the power of the wind, rather then the power of the word of Jesus, be began to sink.
The rhema word from God can be all the time out there for us, but it will not produce results and will not do a miracle for us, if we diminish its power and influence in our life, by our unbelief, by concentrating on something else.
God is ready to give a miracle but if we believe his promises only the half way, we will not see result.