It wasnarrated that Abu Hurairah said:
"The Messenger of Allah (ﷺ)said: 'Does not the one who raises his head before the Imam fearthatAllah may turn his head into the head of a donkey?'" (AR)
English reference (AR): Vol. 1, Book 5, Hadith 961 (AR)
Arabic reference (AR): Book 5, Hadith 1014 (AR)