Musnad Abu Ya'la al-Mawsili 161:56

Musa ibn Muhammad narrated to us, Abdullah ibn Raja’ narrated to us, Qays ibn al-Rabi’ narrated to us, from Ibn Abi al-Safar, from Ibn Sharhabil, from Ibn Abbas, from al-Abbas, who said: I entered upon the Messenger of Allah (may Allah bless him and grant him peace) while his wives were with him. They veiled themselves from me, except Maymunah. A medicine (sa’ut) was pounded for him, and he was administered it (ladud). Then he said: "Let no one remain in the house except that they are administered the medicine, except for al-Abbas, for my right hand did not touch him." Then he said: "Order Abu Bakr to lead the people in prayer." Aisha said to Hafsah: "Tell him that when Abu Bakr stands in that place, he weeps." She told him, and he said: "Order Abu Bakr to lead the people in prayer." So Abu Bakr prayed. Then the Messenger of Allah (may Allah bless him and grant him peace) felt a lightness, so he went out. When Abu Bakr saw him, he stepped back, but he gestured to him with his hand, meaning: "Stay in your place." He came and sat beside him, and the Messenger of Allah (may Allah bless him and grant him peace) recited from where Abu Bakr had finished.