The prayer that prevails is the prayer that is prayed with intensity—the prayer that is offered continually and passionately.
Acts 12 opens with some tragic events in the life of the early church: King Herod had James executed, and he threw Peter into prison. Then we read, "Peter was therefore kept in prison, but constant prayer was offered to God for him by the church" (verse 5).
Think about what they were facing. James, the beloved apostle who was always there with John, had gone to Heaven. It must have been a shock. They were mourning the loss of this great man of God.
And then Herod arrested Peter. It was the night before his trial and potential execution, so they were praying. But their prayer was not just a kick backed yawn: "Lord, help out Peter. . . . What's for dinner?" Rather, it was more like, "Oh, Lord, help Peter! Oh, Lord, deliver Peter!" In fact the word used in this verse for "constant" could be translated "earnestly" or "stretched outwardly." It is the idea of a soul stretching toward an earnest desire. It was praying with agony, with intensity.
The same Greek word is used in Luke 22:44 to describe Jesus' prayer in the Garden of Gethsemane, where "being in agony, He prayed more earnestly."
A lot of times our prayers are so laid back, so casual. Much of our prayer has no power in it because there is no heart in it. Yet the prayer that prevails with God is the prayer into which we put our whole soul, stretching out toward God with intense and agonizing desire. We need to keep bringing our requests to God again and again.
If we put so little heart into our prayers, we can't expect God to put much heart into answering them.