The Ruling on delivering Judgements without Knowledge

Question :

There are some people who deliver judgements withou knowledge, what is the ruling on this?

Answer:

Such an action is among the most dangerous of matters and the greatest of sins; Allah, the Most High has compared speaking about Him without knowledge to associating partners with Him. He said:

Say (O Muhammad): "(But) the things that my Lord has indeed forbidden are Al-Fawahish (great evil sins and every kind of unlawful sexual intercourse) whether committed openly or secretly, sins (of all kinds), unrighteous oppression, joining partners (in worship) with Allah for which He has given no authority, and saying things about Allah of which you have no knowledge."

This includes speaking of Allah without knowledge of His Self, His Attributes, His Actions or His Laws. It is not permissible for anyone to deliver a judgement in any matter unless he knows that this is the Law of Allah, the Almighty, All- Powerful, and unless he has the means and ability to know what the texts from the Book of Allah and the Sunnah of His Messenger demonstrate then he may deliver legal judgements. The Mufti interprets Allah's Words and conveys the Message of Allah's Messenger, so if he says something when he does not know, or is not sure, after looking at and reflecting on the evidences and exercising his Ijtihad therein, then he is guilty of speaking on behalf of Allah and His Messenger without knowledge and he should be prepared for punishment, for Allah, the Almighty, the All-Powerful says:

Then who does more wrong than one who invents a lie against Allah, to lead mankind astray without knowledge. Certainly, Allah guides not the people who are Thalimun (polytheists, wrongdoers, etc.).

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 1 Pages 372-373