My father said, "Messenger of Allah 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 "Samiʿa l-lahu liman hamidah, Rabbana wa laka l-hamd." And he did not do that (i.e. raising his hands) in prostrations.  

أَنَّ رَسُولَ اللَّهِ ﷺ 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