Anas bin Malik reported,

The Messenger of Allah ﷺ fell from a horse — and Sufyan sometimes said "off a horse" — and his right side was scraped. We went in to visit him, and when the time for prayer came, he led us in prayer while seated, so we sat as well. Sufyan once said, "We prayed sitting."When he finished the prayer, he said, "The imam is appointed only to be followed. When he says the takbir, say the takbir. When he bows, bow. When he rises, rise. When he says, 'Allah hears whoever praises Him,' say, 'Our Lord, to You belongs all praise.' And when he prostrates, prostrate."Sufyan said, "This is how Muamar transmitted it."I said, "Yes."He said, "He memorized it well." Likewise Zuhri said, "and to You belongs all praise." "I memorized 'his right side.'"When we left Zuhri, Ibn Jurayj said — and I was with him — "and his right shin was scraped."

Bukhari 805

Sahih

حدثنا علي بن عبد الله قال حدثنا سفيان غير مرة عن الزهري قال سمعت

أنس بن مالك يقول

سقط رسول الله ﷺ عن فرس وربما قال سفيان من فرس فجحش شقه الأيمن فدخلنا عليه نعوده فحضرت الصلاة فصلى بنا قاعدا وقعدنا وقال سفيان مرة صلينا قعودا فلما قضى الصلاة قال إنما جعل الإمام ليؤتم به فإذا كبر فكبروا وإذا ركع فاركعوا وإذا رفع فارفعوا وإذا قال سمع الله لمن حمده فقولوا ربنا ولك الحمد وإذا سجد فاسجدوا قال سفيان كذا جاء به معمر قلت نعم قال لقد حفظ كذا قال الزهري ولك الحمد حفظت من شقه الأيمن فلما خرجنا من عند الزهري قال ابن جريج وأنا عنده فجحش ساقه الأيمن

البخاري 805صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Adhan
Chapter
Descending with takbir when prostrating
Numbering
Darussalam 805
Bukhari 805