“Speak only the speech that neither torments self nor does harm to others. That speech is truly well spoken.”
Right Speech is the third of the eight path factors in the Noble Eightfold Path, and belongs to the virtue division of the path.
“And what is right speech? Abstaining from lying, from divisive speech, from abusive speech, & from idle chatter: This is called right speech.”
The Buddha speaks to his son, Rahula: “Whenever you want to perform a verbal act, you should reflect on it: ‘This verbal act I want to perform — would it lead to self-affliction, to the affliction of others, or to both? Is it an unskillful verbal act, with painful consequences, painful results?’ If, on reflection, you know that it would lead to self-affliction, to the affliction of others, or to both; it would be an unskillful verbal act with painful consequences, painful results, then any verbal act of that sort is absolutely unfit for you to do. But if on reflection you know that it would not cause affliction… it would be a skillful verbal action with happy consequences, happy results, then any verbal act of that sort is fit for you to do.”