´It was narrated that 'Uqbah bin 'Amir said:` "Shall I not show you how I saw the Messenger of Allah (ﷺ) pray?" We said: "Yes." So he stood up and when he bowed, he placed his palms on his knees and put his fingers behind his knees, and held his arms out from his sides, until every part of him settled. Then he raised his head and stood up until every part of him settled. Then he prostrated and held his arms out from his sides, until every part of him settled. Then he sat up until every part of him settled. Then he prostrated again until every part of him settled. Then he did four rak'ahs like that. Then he said: "This is how I saw the Messenger of Allah (ﷺ) pray, and this is how he used to lead us in prayer."
Hadith Referenceسنن نسائي / كتاب التطبيق / 1038
Hadith Gradingالألبانی:صحيح إلا جملة الأصابع | زبیر علی زئی:إسناده حسن
Hadith Takhrij«انظر ما قبلہ (صحیح) (مگر انگلیوں والا ٹکڑا صحیح نہیں ہے)»
Narrated Uqbah ibn Amr al-Ansari: Salim al-Barrad said: We came to Abu Masud Uqbah ibn Amr al-Ansari and said to him: Tell us about the prayer of the Messenger of Allah ﷺ. He stood up before us in the mosque and said the takbir. When he bowed, he placed his hands upon his knees and put his fingers below, and kept his elbows (arms) away from his sides, so everything returned properly to its place. Then he said: "Allah listens to him who praises Him"; then he stood up so that everything returned properly to its place; then he said the takbir and prostrated and put the palms of his hands on the ground; he kept his elbow (arms) away from his sides, so that everything returned to its proper place. Then he raised his head and sat so that everything returned to its place; he then repeated it in a similar way. Then he offered four rak'ahs of prayer like this rak'ah and completed his prayer. Then he said: Thus we witnessed the Messenger of Allah ﷺ offering his prayer.
Shaykh Umar Farooq Saeedi
863. Commentary: ➊ Moderation and tranquility (i'tidal wa itminan) in prayer are obligatory; without them, the prayer becomes invalid. ➋ Placing the hands on the knees, rather, grasping the knees in bowing (ruku') is Sunnah. [سنن نسائي۔ حديث 1035۔ 1036] Whereas the practice of tatbiq (placing one hand over the other between the thighs) has been abrogated. ➌ In bowing (ruku') and prostration (sujud), the elbows should be kept away from the sides.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 863