It is narrated from Sayyiduna Abdullah bin Zam'ah bin al-Aswad bin al-Muttalib bin Asad (may Allah be pleased with him) that he said: When the illness of the Messenger of Allah (peace and blessings be upon him) became severe, and I was with him among a group of Muslims, Sayyiduna Bilal (may Allah be pleased with him) called to the prayer. He (peace and blessings be upon him) said: "Tell someone to lead the people in prayer." I went out and saw that Sayyiduna Umar (may Allah be pleased with him) was among the people, while Sayyiduna Abu Bakr (may Allah be pleased with him) was absent (at that time). I said: "O Umar, stand and lead the people in prayer." So he stood, and when he said the takbir, the Messenger of Allah (peace and blessings be upon him) heard his voice, for Sayyiduna Umar (may Allah be pleased with him) was a man with a loud voice. The Messenger of Allah (peace and blessings be upon him) said: "Where is Abu Bakr? Allah and the Muslims refuse that (anyone other than him should lead)." So he (peace and blessings be upon him) sent for Sayyiduna Abu Bakr (may Allah be pleased with him); he came after Sayyiduna Umar (may Allah be pleased with him) had finished that prayer, and he led the people in prayer. Sayyiduna Abdullah bin Zam'ah (may Allah be pleased with him) says: Sayyiduna Umar (may Allah be pleased with him) said to me: "Woe to you, O Ibn Zam'ah, what have you done to me? By Allah, when you told me to do it, I thought only that the Messenger of Allah (peace and blessings be upon him) had instructed you to do so; otherwise I would not have led the people in prayer." I said: "By Allah, the Messenger of Allah (peace and blessings be upon him) did not instruct me; rather, when I did not find Abu Bakr, I saw you as the most deserving of the prayer among the people present."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14043