James 3:1-5 (ESV)
Not many of you should become teachers, my brothers, for you know that we who teach will be judged with greater strictness.  For we all stumble in many ways, and if anyone does not stumble in what he says, he is a perfect man, able also to bridle his whole body.  If we put bits into the mouths of horses so that they obey us, we guide their whole bodies as well.  Look at the ships also: though they are so large and are driven by strong winds, they are guided by a very small rudder wherever the will of the pilot directs.  So also the tongue is a small member, yet it boasts of great things.
How great a forest is set ablaze by such a small fire!
It strikes me that though this verse is most often spoken about in regards to gossip, James was more speaking to the prevalence of false doctrine being taught even in his day. “Not many of you should become teachers.” This is speaking about teaching falsely rather than rightly. And here I have no truck with James. What he says here is absolutely right, a great forest is set ablaze with even just a little false doctrine.