مختصر صحيح بخاري
Mukhtasar Sahih Bukhari
Book of Adhan (Call to Prayer)
Raising the head before the imam is a grave sin.
Narrated by Abu Huraira (may Allah be pleased with him) from the Prophet Muhammad (peace and blessings be upon him) that he said: "Does not any one of you who raises his head before the Imam fear that Allah may turn his head into the head of a donkey or his appearance into the appearance of a donkey?"
تخریج الحدیث: