Sahih al-Bukhari 735
Book 10: Call to Prayers (Adhaan) · Narrated by Salim bin `Abdullah
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَرْفَعُ يَدَيْهِ حَذْوَ مَنْكِبَيْهِ إِذَا افْتَتَحَ الصَّلاَةَ، وَإِذَا كَبَّرَ لِلرُّكُوعِ، وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ رَفَعَهُمَا كَذَلِكَ أَيْضًا وَقَالَ " سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ، رَبَّنَا وَلَكَ الْحَمْدُ ". وَكَانَ لاَ يَفْعَلُ ذَلِكَ فِي السُّجُودِ.
English translation
Narrated Salim bin `Abdullah:My father said, "Allah's Messenger (ﷺ) used to raise both his hands up to the level of his shoulders when opening the prayer; and on saying the Takbir for bowing. And on raising his head from bowing he used to do the same and then say "Sami`a l-lahu liman hamidah, Rabbana wa laka l-hamd." And he did not do that (i.e. raising his hands) in prostrations
Reference: Sahih al-Bukhari 735, Book of Call to Prayers (Adhaan). English translation by Dr. Muhammad Muhsin Khan.