The Role of Prayer in Public Worship

Reformed worship is built on the conviction that congregational worship is essentially a corporate conversation with God. In some elements of the worship service God speaks to us-in the greeting, the reading of the word, the sermon, the benediction, and so on. In other parts of the worship service the worshipers speak to God-through many of our songs, our commitments, and certainly in our prayers.

The prayers in a worship service constitute a very sacred time in which the corporate voice of God's people is lifted heavenward. Such efforts should never be done unthinkingly, and such prayers should never be written carelessly...

refer below for more details: http://www.calvin.edu/worship/planning/8_22_04.php