The great political philosopher Machiavelli once reveled in the time he spent during his free evenings as a farmer.  He said that he would stay in his room and surround himself with his books.  While reading it would be as if he was conversing with departed intellectual giants.  The same can be applied to working through the writings of the wise men and women who have gone before us in Church History (I would not just limit this principle to theology, but to all disciplines.  It is absurd to discount the wisdom of thinkers from Socrates to Pope John Paul II).  These brothers and sisters (departed saints, of course) can provide clarifications in the Biblical text.  Of course they should never supersede the Bible, but they can also warn you if your interpretation is approaching dangerous grounds theologically.  If I view Jesus as someone who was made, since He is the Son of God, and had a beginning, then Athanasius’ On The Incarnation will help correct this error.  He will force you to go back to the text and reexamine it.  If he says something that is false though then you will have to analyze it deeper.  CS Lewis believed that old books were important to read because, while they might contain errors, those errors have been vetted through history and can be spotted quicker since they are from a different time.  New books have errors in them that we are still steeped in and are more difficult to spot.

The heritage of the Reformation was that all people could read the Bible for themselves.  Indeed while I entirely endorse this idea, we cannot simply be by ourselves.  We must engage with other people in a time-transcending Bible study.  That is why I endorse the reading of Scripture with other solid Christians, both in present and past (read: books) conversations.  Doing so will correct our errors and potentially dangerous, heretical mistakes while also sharpening our minds and deepening our relationships with God who has revealed Himself in Scripture.