When we prophesy, we are speaking the heart of God to a person in need. Prophesy is for edification, exhortation and comfort to person. What might look dead to a person will become alive to them by the power of the Holy Spirit. "So Shall My word be that goes forth from My mouth; it shall not return to Me void but is shall accomplish what I please, and it shall prosper in the thing for which I sent it." Isaiah 55:11 NKJV Remember, it is God's will that will be done. If He spoke it, it will surly come to pass.
"It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit and they are life." John 6:63 NKJV