Sahih al-Bukhari 738
Sahih al-Bukhari · Book 10: Call to Prayers (Adhaan) · To what level should one raise one's hand.
Narrated `Abdullah bin `Umar:
حَدَّثَنَا أَبُو الْيَمَانِ ، قَالَ أَخْبَرَنَا شُعَيْبٌ ، عَنِ الزُّهْرِيِّ ، قَالَ أَخْبَرَنَا سَالِمُ بْنُ عَبْدِ اللَّهِ ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ ـ رضى الله عنهما ـ قَالَ رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم افْتَتَحَ التَّكْبِيرَ فِي الصَّلاَةِ، فَرَفَعَ يَدَيْهِ حِينَ يُكَبِّرُ حَتَّى يَجْعَلَهُمَا حَذْوَ مَنْكِبَيْهِ، وَإِذَا كَبَّرَ لِلرُّكُوعِ فَعَلَ مِثْلَهُ، وَإِذَا قَالَ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ. فَعَلَ مِثْلَهُ وَقَالَ " رَبَّنَا وَلَكَ الْحَمْدُ ". وَلاَ يَفْعَلُ ذَلِكَ حِينَ يَسْجُدُ وَلاَ حِينَ يَرْفَعُ رَأْسَهُ مِنَ السُّجُودِ.
I saw Allah's Messenger (ﷺ) opening the prayer with the Takbir and raising his hands to the level of his shoulders at the time of saying the Takbir, and on saying the Takbir for bowing he did the same; and when he said, "Sami`a l-lahu liman hamidah ", he did the same and then said, "Rabbana wa laka lhamd." But he did not do the same on prostrating and on lifting the head from it."