A lot of times in the church we will find a lot of extra biblical wisdom. It is wisdom in the sense that it might seem to have validity in how to live will.
The interesting part of extra biblical wisdom in the church is that most people often do not realize that this wisdom seems to have originated from somewhere other than the bible. The wisdom doesn't seem to contradict the bible, but it is not directly from the bible, or a direct extension from a biblical principle.
What do we think of this?
It seems the first thing is to realize that this wisdom may be flawed. God did not speak these words and he did not necessarily inspire any man to write them.
There is a lot of decent extra biblical wisdom in the church. It can have benefits, but the reality of this wisdom is a lot of the time it is correct only 80-90% of the time and the other times this wisdom seems very suspect.
When I was a bit younger I was very frustrated because the bible seems often more interested in general principle s about topics then specific advice. Now a bit older I see the wisdom in this approach.
Often overly specific advice can only apply correctly to one specific situation in one place. The bible often does not give specific advice because the nature of wisdom is that a lot of it depends on the context of situations.
This is the sort of reason the bible is the amazing book it is. It does not fall into the trap of giving man exactly what he wants which is cookie cutter answers to life's tough questions.