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