One of the fundamental questions about missions to Muslims is whether it is better to build bridges from Christianity from within Islamic society (i.e. from within the community of the mosque), or to operate as a Christian outsider. Many Christians borrow the contextual strategy that has been so effective in other missionary efforts. They argue that just as one would work from within an indigenous culture to build evangelistic relationships, so then should Christian believers work from within Islamic society or even within the Mosque itself.
George Houssney, director of Horizon International and the creator of the Engaging Islam workshop, responds to this "Insider Movement:"
The purpose of the "Insider Movement" is biblically based. However, the approach is remotely biblical. Jesus came into the world as a Jew and challenged the religious system by calling them out (ekklesia) into a new community which later became the Church universal. To ask converts to remain Muslims is counter productive and renders them fruitless. It is only by stepping out and identifying completely with Christ and his church that the convert can grow and separate himself from the world. Going to the mosque and reading the Quran does not only have intellectual, cultural and social negative ramifications but it is likely to expose them to the demonic.
Using the Quran as a bridge in itself is not the problem. Using it as a divine authority is the problem. There are many insiders who do not quote the Quran as divine authority but rather use it as a bridge to the Bible. However, there are those who do not have a problem with the Quran. The book that has partially inspired the movement is "Building Bridges" by Fouad Accad. This book claims on page 10 that there is noting in the Quran that disagrees with the Bible.