Qays bin Abu Hazim reported,

I was sitting with Abu Bakr al-Siddiq , the successor of the Messenger of Allah ﷺ, a month after the death of the Prophet ﷺ, when he mentioned a story.A call was made among the people that the prayer was to be held in congregation, and this was the first prayer among the Muslims for which such a call was made, announcing that the prayer was to be held in congregation. The people gathered, and he ascended a pulpit that had been made for him, from which he used to deliver sermons. This was the first sermon he delivered in Islam.He praised Allah and extolled Him, then said, "People, I truly wish that someone other than me had been spared this burden. If you hold me to the standard of the practice of your Prophet ﷺ, I cannot bear it. He was protected from Satan, and revelation used to descend upon him from heaven."

حدثنا هاشم بن القاسم قال حدثنا عيسى يعني ابن المسيب

عن قيس بن أبي حازم قال

إني لجالس عند أبي بكر الصديق رضي الله عنه خليفة رسول الله ﷺ بعد وفاة النبي ﷺ بشهر فذكر قصة فنودي في الناس أن الصلاة جامعة وهي أول صلاة في المسلمين نودي بها إن الصلاة جامعة فاجتمع الناس فصعد المنبر شيئا صنع له كان يخطب عليه وهي أول خطبة خطبها في الإسلام قال فحمد الله وأثنى عليه ثم قال يا أيها الناس ولوددت أن هذا كفانيه غيري ولئن أخذتموني بسنة نبيكم ﷺ ما أطيقها إن كان لمعصوما من الشيطان وإن كان لينزل عليه الوحي من السماء