Luck and my e-reader recently brought me to a little gem of a sermon by Jonathan Edwards. It is essentially a manifesto for the thinking Christian, explaining the vital importance of studying your faith. I find it about equal parts encouraging and discouraging that laxity in Christian education was a problem even back in the 1700s. Read it, then act on it:
All Christians should make a business of [improving their knowledge]. They should look upon it as a part of their daily business, and no small part of it neither. It should be attended to as a considerable part of the work of their high calling. … For us to make the improvement of this faculty a business by the bye, is in effect for us to make the faculty of understanding itself a by-faculty, if I may so speak, a faculty of less importance than others: whereas indeed it is the highest faculty we have.
Content not yourselves with having so much knowledge as is thrown in your way, and receive in some sense unavoidably by the frequent inculcation of divine truth in the preaching of the word, of which you are obliged to be hearers, or accidentally gain in conversation; but let it be very much your business to search for it, and that with the same diligence and labour with which men are wont to dig in mines of silver and gold.
And that is why I study (and even teach!) history, and why I read so many old books.
(FYI, you can download this sermon for your e-reader as well).