(Borrowed from the Creedal Christian blog, one of my favorites.)
"I now feel compelled instead to write to encourage you to contend earnestly for the faith that was once for all entrusted to the saints."
Letter of Jude chapter 1 verse 3
No doctrine concerning the divine and saving mysteries of the faith, however trivial, may be taught without the backing of the holy Scriptures. We must not let ourselves be drawn aside by mere persuasion and cleverness of speech. Do not even give absolute belief to me, the one who tells you these things, unless you receive proof from the divine Scriptures of what I teach. For the faith that brings us salvation acquires its force, not from fallible reasonings, but from what can be proved out of the holy Scriptures.
~ St. Cyril of Jerusalem (ca. 313-386)