It is reported that a man saw Ibn ʿAbbās – Allāh be pleased with them – holding the tip of his tongue saying:
Woe to you, say what is good and you will reap gain, and be silent from speaking evil and you will be safe.
The man asked him:
O Ibn ʿAbbās, what is the matter that I see you holding the tip of your tongue saying such-and-such?
It has reached me that the servant of Allāh will not be as angry at anything on the Day of Resurrection as he will be at his tongue.
Imām Aḥmad, Al-Zuhd p236