The Nature of Prayer - Section 1 Mishkat al-Masabih 793

Arabic hadith text
وَعَنِ ابْنِ عُمَرَ: أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يَرْفَعُ يَدَيْهِ حَذْوَ مَنْكِبَيْهِ إِذَا افْتَتَحَ الصَّلَاةَ وَإِذَا كَبَّرَ لِلرُّكُوعِ وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ رَفَعَهُمَا كَذَلِكَ وَقَالَ: سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ رَبَّنَا لَكَ الْحَمْدُ وَكَانَ لَا يَفْعَلُ ذَلِكَ فِي السُّجُودِ
Translation

Ibn ‘Umar said that God’s Messenger used to raise his hands opposite his shoulders when he began prayer and when he said the takbir before bowing; and when he raised his head after bowing he raised them in the same way and said, “God listens to him who praises Him. To Thee, our Lord, be the praise!” But he did not do that when he prostrated himself. (Bukhari and Muslim.)