Not many of you should become teachers,
my fellow believers, because you know that we who teach will be judged
more strictly. We all stumble in many ways. Anyone who is never at fault
in what they say is perfect, able to keep their whole body in check.

When we put bits into the mouths of horses to make them obey us, we can
turn the whole animal. Or take ships as an example. Although they are
so large and are driven by strong winds, they are steered by a very
small rudder wherever the pilot wants to go. Likewise, the tongue is a small part of the body, but it makes great boasts. Consider
what a great forest is set on fire by a small spark. The tongue also is
a fire, a world of evil among the parts of the body. It corrupts the
whole body, sets the whole course of one’s life on fire, and is itself
set on fire by hell.

All kinds of animals, birds, reptiles and sea creatures are being tamed and have been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison.

With the tongue we praise our Lord and Father, and with it we curse human beings, who have been made in God’s likeness. Out of the same mouth come praise and cursing. My
brothers and sisters, this should not be. Can both fresh water and salt
water flow from the same spring? My brothers and sisters, can a fig
tree bear olives, or a grapevine bear figs? Neither can a salt spring
produce fresh water.

- St. James' letter to Christians in the 1st century