(25) باب النَّهْىِ عَنْ سَبْقِ الإِمَامِ، بِرُكُوعٍ أَوْ سُجُودٍ وَنَحْوِهِمَا
Abu Huraira reported:
The Messenger of Allah (ﷺ) said: Does the man who lifts his head before the Imam not fear that Allah may change his face into that of an ass?
Reference: Sahih Muslim 427 b
In-book reference: Book 4, Hadith 126
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 860