If there are 100 people within a denomination or church who do not have a clue,there are at least ten who do,and they continue to witness to the truth.
The same argument can be made against immigration; if out of 100 new immigrants to the USA 10 find the Bible as truth that means 90 do not showing the suicidal policy of Latin immigration; soon the nation will be just another Latin American state. This is the plan and what we see happening.
If 100 Muslims have 10 who have a clue about truth what should they do? The same could be said for Mormons who use the book of Mormon which is an uninspired book.
"The Vatican issued a document Tuesday restating its belief that the Roman Catholic Church is the only true church of Jesus Christ." CBC News (Jul 10, 2007)
Petrus Romanus Lecture