Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ibnmajah:803ʿAlī b. Muḥammad al-Ṭanāfisī > Abū Usāmah > ʿAbd al-Ḥamīd b. Jaʿfar > Muḥammad b. ʿAmr b. ʿAṭāʾ > Abū Ḥumayd al-Sāʿidī

“I heard Abu Humaid As-Sa’idi say: ‘When the Messenger of Allah ﷺ stood up for prayer, he would face the prayer direction, raise his hands, and say: “Allahu Akbar (Allah is Most Great).”  

ابن ماجة:٨٠٣حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ الطَّنَافِسِيُّ حَدَّثَنَا أَبُو أُسَامَةَ حَدَّثَنِي عَبْدُ الْحَمِيدِ بْنُ جَعْفَرٍ حَدَّثَنَا مُحَمَّدُ بْنُ عَمْرِو بْنِ عَطَاءٍ قَالَ

سَمِعْتُ أَبَا حُمَيْدٍ السَّاعِدِيَّ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ إِذَا قَامَ إِلَى الصَّلَاةِ اسْتَقْبَلَ الْقِبْلَةَ وَرَفَعَ يَدَيْهِ وَقَالَ اللَّهُ أَكْبَرُ  


See similar narrations below:

Collected by Tirmidhī
tirmidhi:240ʿAbdullāh b. ʿAbd al-Raḥman

"When Messenger of Allah would enter the Salat he would raise his hands while they were extended."  

الترمذي:٢٤٠قَالَ وَحَدَّثَنَا عَبْدُ اللَّهِ بْنُ عَبْدِ الرَّحْمَنِ أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ عَبْدِ الْمَجِيدِ الْحَنَفِيُّ حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ عَنْ سَعِيدِ بْنِ سِمْعَانَ قَالَ

سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ إِذَا قَامَ إِلَى الصَّلاَةِ رَفَعَ يَدَيْهِ مَدًّا  

قَالَ أَبُو عِيسَى قَالَ عَبْدُ اللَّهِ بْنُ عَبْدِ الرَّحْمَنِ وَهَذَا أَصَحُّ مِنْ حَدِيثِ يَحْيَى بْنِ الْيَمَانِ وَحَدِيثُ يَحْيَى بْنِ الْيَمَانِ خَطَأٌ