From Sahih Muslim (Hadith 947):
Anas reported:The Apostle of Allah (ﷺ) did not come to us for three days. When the prayer was about to start. Abu Bakr stepped forward (to lead the prayer), and the Messenger of Allah (ﷺ) lifted the curtain. When the face of the Messenger of Allah (ﷺ) became visible to us, we (found) that no sight was more endearing to us than the face of the Messenger of Allah (ﷺ) as it appeared to us. The Apostle of Allah (ﷺ) with the gesture of his hand directed Abu Bakr to step forward (and lead the prayer). The Apostle of Allah (ﷺ) then drew the curtain, and we could not see him till he died
Reference: Muslim 947