There is an important doctrine called the 'perspicuity of Scripture' or, a little simpler in language, 'the clarity of Scripture'.
As I understand this doctrine (over which there are interesting debates) most can agree that Scripture in respect of its main message of salvation is 'clear' - the ploughman and the barmaid can understand it through reading or hearing Scripture. Things are not so unified if the doctrine is pressed to mean that any reader of Scripture (i.e. with or without education in theology and biblical studies) can understand any part of it so long as (say) they follow a simple interpretative strategy such as allowing 'Scripture to interpret Scripture'.
When evangelicals press the doctrine there is an interesting paradox going on because evangelicals typically press the case for preaching - substantial sermons at every service, if not every meeting of the church. If Scripture is wholly clear, why preach it and not just read it? (!!)
The fact is that parts of Scripture are not easy to understand, or are capable of different interpretations, not all of which are necessarily true. The point and privilege of preaching is the opportunity and responsibility it provides for the preacher to explain the meaning of the passage under consideration.
One such passage occurs tomorrow, Sunday 9th November, in our NZPB two year cycle: Luke 16:1-13.
Actually, this gospel passage is so difficult to interpret I defy any preacher to make perfectly good sense of it!!!!!!!!!!!!