Idle Chatter

"Whereas some priests and contemplatives, living off food given in faith, are addicted to talking about lowly topics such as these — talking about kings, robbers, ministers of state; armies, alarms, and battles; food and drink; clothing, furniture, garlands, and scents; relatives; vehicles; villages, towns, cities, the countryside; women and heroes; the gossip of the street and the well; tales of the dead; tales of diversity [philosophical discussions of the past and future], the creation of the world and of the sea, and talk of whether things exist or not — he abstains from talking about lowly topics such as these. This, too, is part of his virtue.

"Whereas some priests and contemplatives, living off food given in faith, are addicted to debates such as these — 'You understand this doctrine and discipline? I'm the one who understands this doctrine and discipline. How could you understand this doctrine and discipline? You're practicing wrongly. I'm practicing rightly. I'm being consistent. You're not. What should be said first you said last. What should be said last you said first. What you took so long to think out has been refuted. Your doctrine has been overthrown. You're defeated. Go and try to salvage your doctrine; extricate yourself if you can!' — he abstains from debates such as these. This, too, is part of his virtue."

- Buddha
Samaññaphala Sutta

This is advice for monastics. Details of right speech were given in this post