I saw Malik bin Huwairith saying Takbir and raising both his hands (on starting the prayers and raising his hands on bowing and also on raising his head after bowing. Malik bin Huwairith said, "Messenger of Allah ﷺ did the same."  

أَنْ يَرْكَعَ رَفَعَ يَدَيْهِ وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ رَفَعَ يَدَيْهِ وَحَدَّثَ أَنَّ رَسُولَ اللَّهِ ﷺ صَنَعَ هَكَذَا  

[Machine] Certainly, the Prophet ﷺ used to "when he performed the takbeer, he would raise his hands until they were level with his ears, and when he intended to bow, and when he raised his head from bowing."  

أَنَّ النَّبِيَّ ﷺ كَانَ «إِذَا كَبَّرَ رَفَعَ يَدَيْهِ حَتَّى يُحَاذِيَ أُذُنَيْهِ وَإِذَا أَرَادَ أَنْ يَرْكَعَ وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ»  

Abu Qilaba reported that he saw Malik b. Huwairith raising his hands at the beginning of prayer and raising his hands before kneeling down, and raising his hands after lifting his head from the state of kneeling, and he narrated that the Messenger of Allah ﷺ used to do like this. (Using translation from Muslim 391a)  

أَنَّهُ رَأَى مَالِكَ بْنَ الْحُوَيْرِثِ «إِذَا صَلَّى كَبَّرَ وَرَفَعَ يَدَيْهِ وَإِذَا أَرَادَ أَنْ يَرْكَعَ رَفَعَ يَدَيْهِ وَإِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ رَفَعَ يَدَيْهِ وَحَدَّثَ أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يَفْعَلُ هَكَذَا»