How is above of under/above rightly dividing the word of truth, and right of left/right wrongly dividing it?

You will never understand the Bible as long as you begin with the prejudice that it is flawed and contradictory. In fact, there are no contradictions in the Bible at all. Obviously (see question), there are severe problems with the ways in which people misinterpret the Bible. That would be the wrongly dividing to which you allude.