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. (Using translation from Bukhārī 735)
أَنَّ رَسُولَ اللهِ ﷺ كَانَ إِذَا افْتَتَحَ الصَّلَاةَ رَفَعَ يَدَيْهِ حَذْوَ مَنْكِبَيْهِ وَإِذَا رَفَعَ مِنَ الرُّكُوعِ رَفَعَهُمَا كَذَلِكَ وَقَالَ سَمِعَ اللهُ لِمَنْ حَمِدَهُ رَبَّنَا وَلَكَ الْحَمْدُ وَكَانَ لَا يَفْعَلُ ذَلِكَ فِي السُّجُودِ