"Too many believers have weak prayer lives because they DON'T believe their prayers accomplish anything.
They petition the Lord for something and then forget about it, acting as if they knew in advance that God wouldn't be at all compelled to grant what they requested.
Even in the early days of the church, when faith generally was strong and vital, prayer could be passive and unexpectant.
When the apostle Peter was imprisoned in Jerusalem, a group of concerned believers met at the house of Mary, John Mark's mother, to pray for his release (Acts 12:12).
As they were doing so, an angel of the Lord miraculously delivered Peter from his chains (vv. 7–10).
While the believers were still praying, Peter arrived at the house and knocked on the door.
A servant girl named Rhoda answered the door, and upon recognizing Peter's voice, she turned around and rushed to tell the others before letting Peter in (vv. 13–14).
The others did not believe her, however, until they finally let Peter in.
Then "they saw him and were amazed"
They apparently had been praying for what they did not really believe would happen.
We must pray in faith, believing that our prayers do make a difference to God."
Because they do!