Imaam Ahmad Ibn Hanbal (رحمه الله) said:
“All praise is due to Allaah who, in every age and interval between the Prophets, raises up a group from the people of knowledge, who call the misguided to guidance, patiently bearing ill-treatment and harm. With the Book of Allaah they give life to the dead and with the Light of Allaah they give sight to the blind. How many a person killed by Iblees (the Devil) they have revived. How beautiful their effect has been upon the people, and how vile the people have been towards them. They expel from the Book of Allaah the alterations of those going beyond bounds, the false claims of the liars and the false interpretations of the ignorant-ones – those who uphold the banner of innovation and let loose the trials and discords; who upon the Book, oppose the Book and agree upon opposing the Book. They speak about Allaah and his Book without knowledge, argue about what is ambiguous in the Book, and deceive the ignorant ones with such ambiguities. We seek refuge in Allaah from the trials of the misguided ones.”
— [ar-Radd ‘alal Jahmiyyah waz-Zanaadiqah (p. 2) of Imaam Ahmad Ibn Hanbal]