Nahj al-Balagha Hadith n. 392

Selections from The Sayings and Preaching of Amir al-Muminin Ali ibn Abi Talib (Peace Be Upon Him) Including His Replies to Questions and Maxims Expressed for Various Purposes.
Translated by Sayyid Ali Reza

وَقَالَ (عليه ‏السلام):

Amir al-mu'minin, peace be upon him, said:

تَكَلَّمُوا تُعْرَفُوا،

Speak so that you may be known,

فَإِنَّ الْمَرْءَ مَخْبُوءٌ تَحْتَ لِسَانِهِ.

since man is hidden under his tongue.