You might find something in the quotes under the categories, "Religion-Verify", and "Religion-Do Not Verify" at http://www.reexamine.org/quotes/admin-site-map.htm#beliefs.
I know this one says we should research old publications:
"Their zeal for knowledge may even prompt them to dig back into things that were published long before they came into the truth, expanding and deepening their understanding, and ever growing in Christian maturity... Do you dig out older publications to expand and deepen your knowledge on subjects about which questions arise? Have you really studied these earlier publications?... How is your background of knowledge? ... Never think: "Oh, I know most of that." For you will find, indeed, that you do not and that you will be strengthened by your additional study...once you have completed your study of them you can then look to even older publications... Only by studying earlier publications and digging back through previous issues of The Watchtower kept in the library at your local Kingdom Hall. There is much in the way of spiritual riches and aids toward mature knowledge in these earlier publications, and their study is most certainly worth your time."--Watchtower May 15, 1957 pp.313-315
Here's another gem:
"One God alone could be supreme and all-powerful; and one such God could mean only one true religion, namely, the one right worship of this one supreme, almighty God. His religion is one of right belief and is harmonious in all its expressions, just as true physical science is harmonious and not self-contradictory. The true religion of the one God does not disagree with itself, deny itself or get divided with itself. If it had internal disagreement, contradiction and disunity, it could never stand; it could not be simple truth; it would disagree with the scientific laws of the universe; it could not triumph in the long-drawn-out conflict between true religion and false. But true religion must triumph, because truth cannot be destroyed. That is why, despite all the many false religions in the world, the true religion has lived through till this day..."--Watchtower 11/15/1963