From Sahih Muslim (Hadith 942):
A'mash reported:When the Messenger of Allah (ﷺ) suffered from illness of which he died, and in the hadith transmitted by Ibn Mus-hir, the words are: The Messenger of Allah (ﷺ) was brought till he was seated by his (Abu Bakr's) side and the Apostle (ﷺ) led the people in prayer and Abu Bakr was making takbir audible to them, and in the hadith transmitted by 'Isa the (words are):" The Messenger of Allah (ﷺ) sat and led the people in prayer and Abu Bakr was by his side and he was making (takbir) audible to the people
Reference: Muslim 942