Sunan Abi Dawud, Hadith 723 ⓘ
Wa’il b.Hujr said: He saw that when the Prophet stood up to pray he raised his hands till they were in front of his shoulders and placed his thumbs opposite his ears; then he uttered the Takbir (Allah is most great).
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ الرَّحِيمِ بْنُ سُلَيْمَانَ، عَنِ الْحَسَنِ بْنِ عُبَيْدِ اللَّهِ النَّخَعِيِّ، عَنْ عَبْدِ الْجَبَّارِ بْنِ وَائِلٍ، عَنْ أَبِيهِ، أَنَّهُ أَبْصَرَ النَّبِيَّ صلى الله عليه وسلم حِينَ قَامَ إِلَى الصَّلاَةِ رَفَعَ يَدَيْهِ حَتَّى كَانَتَا بِحِيَالِ مَنْكِبَيْهِ وَحَاذَى بِإِبْهَامَيْهِ أُذُنَيْهِ ثُمَّ كَبَّرَ .
also referenced under: Hadith 724 (DarusSalam)