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.
bayhaqi:2537Abū Saʿīd b. Abū ʿAmr > Abū al-ʿAbbās Muḥammad b. Yaʿqūb > al-Rabīʿ b. Sulaymān > Lilshhāfiʿī Mā Maʿná Rafʿ al-Yadayn ʿInd al-Rukūʿ

[Machine] like the meaning of raising them at the beginning as a glorification of Allah, and it is a followed Sunnah in which the reward of Allah is hoped for, and like raising the hands at Safa and Marwa and others.  

البيهقي:٢٥٣٧أَخْبَرَنَا أَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ أنبأ الرَّبِيعُ بْنُ سُلَيْمَانَ قَالَ قُلْتُ لِلشَّافِعِيِّ مَا مَعْنَى رَفْعِ الْيَدَيْنِ عِنْدَ الرُّكُوعِ؟ فَقَالَ

مِثْلُ مَعْنَى رَفَعِهَمَا عِنْدَ الِافْتِتَاحِ تَعْظِيمًا لِلَّهِ وَسُنَّةٌ مُتَّبَعَةٌ يُرْجَى فِيهَا ثَوَابُ اللهِ ﷻ وَمِثْلُ رَفْعِ الْيَدَيْنِ عَلَى الصَّفَا وَالْمَرْوَةِ وَغَيْرِهِمَا