´It was narrated that Salim said:` "We came to Abu Mas'ud and said to him: 'Tell us about the prayer of the Messenger of Allah (ﷺ).' He stood in front of us and said the takbir, then when he bowed he placed his palms on his knees and put his fingers lower than that, and he held his elbows out from his sides until every part of him had settled. Then he said: Sami' Allahu liman hamidah, Rabbana wa lakal-hamd (Allah hears those who praise Him, our Lord, and to You be the praise), then he stood up until every part of him had settled."
Hadith Referenceسنن نسائي / كتاب التطبيق / 1037
Hadith Gradingالألبانی:صحيح إلا جملة الأصابع | زبیر علی زئی:إسناده حسن
Hadith Takhrij«سنن ابی داود/الصلاة 148 (863) مطولاً، (تحفة الأشراف: 9985)، مسند احمد 4/119، 120 و 5/274، سنن الدارمی/الصلاة 68 (1343) (صحیح) (متابعات اور شواہد سے تقویت پاکر یہ روایت بھی صحیح ہے، مگر ’’انگلیوں والا‘‘ ٹکڑا صحیح نہیں ہے، کیوں کہ اس کے راوی ’’عطاء بن السائب‘‘ مختلط راوی ہیں، اور ’’ابو الاحوص‘‘ یا زائدہ یا ابن علیہ (جو اگلی روایتوں میں ان کے راوی ہیں) ان سے اختلاط کے بعد روایت کرنے والے ہیں، اور انگلیوں والے ٹکڑے میں ان کا کوئی متابع نہیں پایا جاتا)»
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