Recently there was a gathering of leading theologians and pastors called the Gospel Coalition. This gathering was for the purpose of centralizing the gospel and historic theology across denominational lines. This is an appropriate form of ecumenism. I encourage you to visit the site and see what you think. Particularly I want to encourage you to go HERE for their resource library. You will find articles and media that is exceptional. Look for “Contemporary” on this linked page and click on “Islam”. It is a fantastic introduction and testimony on the subject.