Usul al-Kafi
Book 2: The Book of Excellence of Knowledge

Chapter 11

Traditions 78 to 84
Prohibition of speaking without knowledge

78. 1. Imam Jafar as-Sadiq (p): I warn you against two tendencies which lead to perdition of Mankind. Do not resort to wrong ways with respect of the Divine Religion and do not announce your verdict on matters which you do not know.(B2, C11, T1)

79. 2. Imam Jafar as-Sadiq (p): I warn you against two tendencies that have caused destruction to people. Beware of announcing your judgment on the basis of your personal opinion before the people. And beware of treating anything as permissible without due knowledge.(B2, C11, T2)

80. 3. Imam Muhammad al-Baqir (p): One who pronounces his verdict (on religious matters) before people without due knowledge and proper guidance is cursed by the angels of mercy as well as by the angels of chastisement and he is also responsible for the sin of those who act according to that verdict.(B2, C11, T3)

81. 4. Imam Muhammad al-Baqir (p): Speak only about what you know. Regarding what you do not know say ‘God knows best’. Verily, a person may single out any verse from the Noble Quran (and interpret it wrongly) and may fall down deeper than the distance between the Heaven and the Earth…(B2, C11, T4)

82. 7. Imam Muhammad al-Baqir (p) was asked: What is the right of God over His servants?
The Imam (p): They should say what they know and maintain silence in case they do not know.(B2, C11, T7)

83. 8. Imam Jafar as-Sadiq (p): Verily God, the Mighty, the Majestic, has especially warned His Servants in two verses of His Book. Firstly, that they should not say anything without definite knowledge and that they should never insist on what they do not know.
The Imam (p) then quoted two verses of the Noble Quran which are as follows:
Was not a Covenant of the Book (of Law) taken from them that they will not speak about God save the truth? (Q, 7:169)
Nay! They belied that which they comprehended not with the knowledge of it and the explanation of it comes not unto them (Q, 10:39).(B2, C11, T8)

84. 9. Prophet Muhammad (p): …Whoever acts on the basis of faulty conclusions (in religious matters) is doomed and brings others to their doom and whoever issues a prescript (an edict) without any knowledge of the abrogated verses (of the Noble Quran) and of those verses that have abrogated them and without any knowledge of those verses which are precise in meaning and of (those that are) ambiguous, meets his doom and brings others to their doom.(B2, C11, T9)