This is one of the best posts I have read in a while.
Here is an excerpt:
You realize, of course, that this makes our study of theology less outwardly secure. We cannot simply compile a list of "safe" authors, stamp them with the Reformed equivalent of imprimatur or nihil obstat, and then confine our reading to them.
We must do the hard work of exercising discernment - sentence by sentence, paragraph by paragraph, argument by argument. Facts, insights, perspectives, and methods must all be tested in the light of the principles of Scripture.
And we must keep alive our consciousness of dependence on Christ, in whom are hidden all the treasures of wisdom and knowledge. Our safety is not in avoiding the ideas of the unbelieving world; our safety is in union with Christ, who transforms the mind of those who trust in him.