حَدَّثَنَا يَحْيَى حَدَّثَنَا مَالِكٌ حَدَّثَنِي الزُّهْرِيُّ عَنْ سَالِمٍ عَنْ أَبِيهِ قَالَ كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا افْتَتَحَ الصَّلَاةَ رَفَعَ يَدَيْهِ حَذْوَ مَنْكِبَيْهِ وَإِذَا رَكَعَ صَنَعَ مِثْلَ ذَلِكَ وَإِذَا رَفَعَ رَأْسَهُ مِنْ الرُّكُوعِ صَنَعَ مِثْلَ ذَلِكَ وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ قَالَ رَبَّنَا وَلَكَ الْحَمْدُ وَلَا يَصْنَعُ مِثْلَ ذَلِكَ فِي السُّجُودِ
مسند امام احمد بن حنبل · Hadith 4674
It was narrated from Saalim that his father said: When the Messenger of Allah (PBUH) started to pray, he would raise his hands until they were level with his shoulders, and when he bowed he did the same thing, and when he rose from bowing he did the same thing. And when he said: Allah hears the one who praises Him (Sami'a Allahu liman hamidah), he said: Char Lord to You be praise (Rabbana wa laka al-hamd). And he did not do that when he prostrated.
Sanad
حَدَّثَنَا يَحْيَى حَدَّثَنَا مَالِكٌ حَدَّثَنِي الزُّهْرِيُّ عَنْ سَالِمٍ عَنْ أَبِيهِ