I recently acquired the Dictionary of Mission Theology edited by John Corrie. Under the "Prayer" entry, D.R.J. Evans concludes his contribution with this observation:
It is striking that the content of much of the intercessory prayer material recorded in the NT has to do with the process of sanctification of God's chosen people. Paul was not always praying that the churches around the Mediterranean would be more outward looking, develop five-year evangelistic plans and move from maintenance to missions! But he was always praying that converted men and women would become increasingly holy and, by so becoming, adorn the doctrine of the gospel, providing thereby a magnetic and attractive power to draw people to Christ (e.g. Col. 1:9-14). It is the transformation of the lives of Christian converts that is the most powerful witness in society and the best propaganda for mission.
Similarly Paul's intercessory prayers focus on the converts' working faith, love-inspired labour and hope-filled endurance (I Thess. 1:3), which all have significant consequences for mission (v. 10). Holiness of life with a transformed lifestyle spreads the gospel message and promotes mission. If the life speaks louder than the lips, then more intercession for holiness is needed for effective mission.
The Queen of Sheba had her breath taken away by her experience of the wisdom of Solomon and the magnificence of the Jerusalem temple. Men and women worldwide wait to be confronted by the transformed lives of God's saints by the Holy Spirit. Praying for holiness means praying to be attractive visual aids in the cause of the missio Dei in the world. Intercessory prayer and worldwide mission are umbilically linked."