Musnad Ahmad #678

It was narrated from ‘Ali bin Abi Talib (رضي الله عنه) that when the Messenger of Allah (ﷺ) stood up to offer the prescribed prayer, he would say Allahu Akbar and raise his hands to shoulder height; he did the same when he finished reciting and wanted to bow, and he did it when he raised his head from bowing. He did not raise his hands when sitting in any part of his prayer, but when he stood up following the two prostrations, he raised his hands in the same manner and said Allahu Akbar.