Prayer is one of the mysteries of the kingdom, it is an advantage given to the believer to tap into a realm higher than the realm of men. Ordinary people have done wonders on earth by partnering with the realm of the spirit through prayer. The power of prayer is not in the activity but in its consistency. Many believers pray but do not know how to pray. The mystery is a hidden code of operation. They require the agency of the spirit and regeneration of the believer.
You do not know how cheap the devil is until you understand the mystery of prevailing prayers.