He said to him, "Tell us about the prayer of the Messenger of Allah ﷺ."So he stood before us and said the takbir. When he bowed, he placed his palms on his knees with his fingers below that, and held his elbows away from his sides until every part of him was settled. Then he said, "Allah hears whoever praises Him," and rose until every part of him was settled.
أخبرنا هناد بن السري في حديثه عن أبي الأحوص عن عطاء بن السائب عن سالم قال أتينا
له حدثنا عن صلاة رسول الله ﷺ فقام بين أيدينا وكبر فلما ركع وضع راحتيه على ركبتيه وجعل أصابعه أسفل من ذلك وجافى بمرفقيه حتى استوى كل شيء منه ثم قال سمع الله لمن حمده فقام حتى استوى كل شيء منه
[Its chain of transmission is hasan] Abu Dawud narrated it in Kitab al-Salah, in the chapter on the prayer of one who does not keep his back straight in ruku and sujud, hadith no. 863, from the hadith of Ata bin Saaib, transmitted through him. It is also found in Sunan al-Kubra, hadith no. 624. Ibn Khuzayma graded it sahih, hadith no. 598, as did Hakim, 1/224, and Dhahabi.Abu Masud is Uqba bin Amr, and Salim is al-Barrad. Ata narrated this before his memory became confused, and it was transmitted from him by Ibn Ulaya and Zaida. See the hadith that follows and the one after it.