Abdullah bin Zama reported,

When the Messenger of Allah ﷺ became gravely ill, I was with him among a group of Muslims. Bilal called for the prayer, and the Messenger of Allah ﷺ said, "Tell someone to lead the people in prayer."So I went out, and there I found Umar among the people, while Abu Bakr was absent. I said, "Stand, Umar, and lead the people in prayer."He stood up, and when Umar said the opening takbir, the Messenger of Allah ﷺ heard his voice, for Umar was a man with a loud voice. The Messenger of Allah ﷺ said, "Where is Abu Bakr? Allah and the Muslims refuse anyone but him. Allah and the Muslims refuse anyone but him."He sent for Abu Bakr, who came after Umar had finished that prayer, and Abu Bakr then led the people in prayer.Abdullah bin Zama said, Umar said to me, "Woe to you, what have you done to me, son of Zama? By Allah, when you ordered me, I thought only that the Messenger of Allah ﷺ had instructed you to do so. Otherwise, I would never have led the people in prayer."I replied, "By Allah, the Messenger of Allah ﷺ did not order me, but when I did not see Abu Bakr, I considered you the most worthy of those present to lead the prayer."

عن عبد الله بن زمعة بن الأسود بن المطلب بن أسد قال

لما استعز برسول الله ﷺ وأنا عنده في نفر من المسلمين، قال: دعا بلال للصلاة، فقال: مروا من يصلي بالناس قال: فخرجت فإذا عمر في الناس، وكان أبو بكر غائبا، فقال: قم يا عمر، فصل بالناس. قال: فقام، فلما كبر عمر سمع رسول الله ﷺ، صوته، وكان عمر رجلا مجهرا، قال: فقال رسول الله ﷺ: فأين أبو بكر؟ يأبى الله ذلك والمسلمون، يأبى الله ذلك والمسلمون قال: فبعث إلى أبي بكر، فجاء بعد أن صلى عمر تلك الصلاة، فصلى بالناس. قال: وقال عبد الله بن زمعة: قال لي عمر: ويحك، ماذا صنعت بي يا ابن زمعة، والله ما ظننت حين أمرتني إلا أن رسول الله ﷺ أمرك بذلك، ولولا ذلك ما صليت بالناس. قال: قلت: والله ما أمرني رسول الله ﷺ ولكن حين لم أر أبا بكر رأيتك أحق من حضر بالصلاة.