To raise both hands while saying the Takbir [on opening As-Salat (the prayer)], and while bowing and on raising up the head (after bowing)
حَدَّثَنَا مُحَمَّدُ بْنُ مُقَاتِلٍ، قَالَ أَخْبَرَنَا عَبْدُ اللَّهِ، قَالَ أَخْبَرَنَا يُونُسُ، عَنِ الزُّهْرِيِّ، أَخْبَرَنِي سَالِمُ بْنُ عَبْدِ اللَّهِ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، رضى الله عنهما قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم إِذَا قَامَ فِي الصَّلاَةِ رَفَعَ يَدَيْهِ حَتَّى يَكُونَا حَذْوَ مَنْكِبَيْهِ، وَكَانَ يَفْعَلُ ذَلِكَ حِينَ يُكَبِّرُ لِلرُّكُوعِ، وَيَفْعَلُ ذَلِكَ إِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ وَيَقُولُ " سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ ". وَلاَ يَفْعَلُ ذَلِكَ فِي السُّجُودِ.
Narrated `Abdullah bin `Umar: I saw that whenever Allah's Messenger (ﷺ) stood for the prayer, he used to raise both his hands up to the shoulders, and used to do the same on saying the Takbir for bowing and on raising his head from it and used to say, "Sami`a l-lahu liman hamidah". But he did not do that (i.e. raising his hands) in prostrations.