question #1 Sahih Muslim Introduction 34, Introduction, Narration 33 : What are the consequences of speaking without knowledge in Islam?

‘By Allah, indeed it is a grave matter that the likes of you, a descendent of two Imāms of guidance – meaning Umar and Ibn Umar – is asked about a matter and you have no knowledge of it’. So [al-Qāsim] said: ‘By Allah, more grave than that according to Allah, and to whoever reflects about Allah, is to speak without knowledge or to report on authority of one who is not trustworthy’. [Ibn Uyaynah] said that Abū Aqīl Yahyā bin al-Mutawakkil witnessed them both when they said that.