There was a question about Sola Scriptura from another post of mine, and my response became so long, I decided to make it into another blog post. So here it is:
There are people who would only believe something if it were stated in the Bible. The problem is that is not the original intent of Luther's Sola Scriptura.
Luther's development of this theological point was in reference to the Roman Catholic Church asserting various theological truths based on tradition. This was usually done with a political purpose, including maintaining the power of this institutional church and its leaders. As Luther began investigation Scripture, he argued that not all of these theological points were accurate, but the church once again argued against him based on tradition and threatened his life more than once.
Therefore, in contrast to a tradition-based theology, Luther went to the other spectrum, stating that we should only develop theology based on Scripture. That's why he also advocated for all people having the right to read the Bible (previously, only priests were able to do so). He made the first German language translation in order for the masses to be able to read the Bible and therefore challenge beliefs based on tradition.
This is the origin of why many Protestant churches advocate that everyone own and read the Bible and why many Protestant denominations are less hierarchical than the Catholic Church.
The problem is that many people have taken it to the extreme, arguing that if it is not in the Bible, it is not truth. Further, interpretation of the Bible is done out of context. Again, if we hold literally true to Sola Scriptura, then we need not understand other things like psychology, sociology, history, biology, physics, etc. in order to understand Scripture. This obviously creates many theological and interpretation problems, yet many Christians do not even realize they have faced these problems. This article describes some of these problems, too.
We need to interpret the world around us through the lens of the Bible, while interpreting the Bible with the information gleaned from the world.