Nahj al-Balagha Hadith n. 382

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:

لاَ تَقُلْ مَا لاَ تَعْلَمُ،

Do not say what you do not know;

بَلْ لاَ تَقُلْ كُلَّ مَا تَعْلَمُ،

rather do not say all that you know,

فَإِنَّ اللهَ سبحانه قد فَرَضَ عَلَى جَوَارِحِكَ كُلِّهَا فَرَائِضَ يَحْتَجُّ بِهَا عَلَيْكَ يَوْمَ الْقِيَامَةِ.

because Allah has laid down some obligations for all your limbs by means of which He will put forth arguments against you on the Day of Judgment.