Abu Dhar (r.a.) said: “I was with the Prophet (PBUH) one day and I heard him saying: “There is something I fear for my Ummah more than the Dajjal.” It was then that I became afraid, so I said: “Oh Rasool Allah! Which thing is that?” He (S.A.W) said; “Misguided Scholars”.

Reference: [Musnad Ahmad (5/145) No. 21334 and 21335]