A person's speech has an enormous influence for good or ill and is a sure guide to character.
The impact of speech
It has the power of life and death
See also
It can bring ruin or joy to the speaker
It can destroy others
It can bring life to others
The timing of speech
There is an appropriate time for speaking
There is an appropriate time for silence
Spoken witness produces faith
Jesus Christ was silent before his accusers
pp Mk 14:61
pp Mk 15:5
Speech is an expression of a person's character
pp Mk 7:14-23