Abu Bakr was leading them in prayer during the illness from which the Prophet ﷺ died. When Monday came, the Messenger of Allah ﷺ drew back the curtain of the chamber and saw Abu Bakr leading the people in prayer.The narrator said, "I looked at his face, and it was like a page of the Quran, and he was smiling. We nearly lost our composure in the prayer out of joy at seeing the Messenger of Allah ﷺ."Abu Bakr made to step back, but the Prophet ﷺ motioned to him to stay as he was. Then he let the curtain fall, and he passed away that very day.Umar stood up and said, "The Messenger of Allah ﷺ has not died. Rather, his Lord has summoned him just as He summoned Musa, who stayed away from his people for forty nights. By Allah, I truly hope the Messenger of Allah ﷺ will live until he cuts off the hands and tongues of certain hypocrites who claim," or he said, "who say, that the Messenger of Allah ﷺ has died."
حدثنا أبو اليمان قال أخبرنا شعيب عن الزهري قال أخبرني أنس بن مالك وكان مع النبي ﷺ وخدمه وصحبه أن أبا بكر كان يصلي لهم في وجع النبي ﷺ الذي توفي فيه حتى إذا كان يوم الاثنين فذكر الحديث
Its isnad is sahih. Abu Yaman is Hakam bin Nafi Himsi, the trustworthy narrator, and Shuayb is Ibn Abu Hamza. Both are trustworthy, except that it has been said that Abu Yaman's narrations from Shuayb were by munawala. In any case, the hadith has already been given with a chain of the preserving imams.