James 3:1-5

Not many should become teachers, my brothers,  because you know that we will receive a stricter judgment.  For we all stumble in many ways.  If anyone does not stumble in what he says, he is mature, able also to control the whole body.  Now if we put bits into the mouths of horses so that they obey us,  we direct their whole bodies. And consider ships: Though very large and driven by fierce winds, they are guided by a very small rudder wherever the will of the pilot directs. So too, though the tongue is a small part of the body, it boasts great things.  Consider how a small fire sets ablaze a large forest.