Sunan an-Nasa'i 876

It was narrated that Ibn Umar said:I saw the Messenger of Allah (ﷺ) when he said the opening Takbir of the prayer, raise his hands until they were level with his shoulders. When he said the Takbir before bowing he did likewise, and when he said: 'Sami Allahu liman hamidah (Allah hears those who praise Him),' he did likewise, then he said: 'Rabbana wa lakal-hamd (Our Lord, to You be praise).' But he did not do that when he prostrated or when he raised his head from prostration