The Holy Bible says,

If anyone is never at fault in what he says, he is a perfect man, able to keep his whole body in check. (James 3:2).

The tongue is a small part of the body, but it makes great boasts.

The tongue also is a fire, a world of evil among the parts of the body. (James 3:5).

It corrupts the whole person, sets the whole course of his life on fire,...(James 3:6).

No man can tame the tongue. It is a restless evil, full of deadly poison. (James 3:8).