Syedna Suleman Alaihi Salatu Wasalam told: If discussion is Silver then Silence is Gold.
Prophet Syedna Muhammad Sal Allahu Alaihi Wasalam said: if you guarantee protection of the boneless meat between your jaws (toung) and prptection of the one between you legs (private part) then Jannat is guaranteed for such person.
Imam Ghazali r.t.a said:
Tounge is a free organ of body,
The knowledge to knew what and when to say is very difficult to get and if obtained it is hard to control the tounge.