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?'" (FR)
English reference (FR): Vol. 1, Book 5, Hadith 961 (FR)
Arabic reference (FR): Book 5, Hadith 1014 (FR)