Riyad as-Salihin
Riyad as-Salihin 1751
Prohibition of raising one's Head before the Imam
Arabic hadith text
عن أبي هريرة رضي الله عنه أن النبي صلى الله عليه وسلم قال: "أما يخشى أحدكم إذا رفع رأسه قبل الإمام أن يجعل الله رأسه رأس حمار! أو يجعل الله صورته صورة حمار" ((متفق عليه)).
Translation
Abu Hurairah (May Allah be pleased with him) said
The Prophet (ﷺ) said, "Does he who raises up his head before the Imam not fear that Allah will make his head that of a donkey or make his appearance similar to that of donkey?"[Al-Bukhari and Muslim].