Sunan an-Nasa'i, 879

It was narrated from Abdul-Jabbar bin Wa'il that his father said:"I prayed behind the Messenger of Allah (ﷺ) and when he started to pray he said the Takbir and raised his hands until they were in level with his ears. Then he recited the Opening of the Book, and when he had finished he said 'Amin' and raised his voice with it

Rapporté par Abdul-Jabbar bin Wa’il, d’après son père : J’ai prié derrière le Messager d’Allah (ﷺ) et, lorsqu’il commença la prière, il dit le takbir et leva les mains jusqu’à ce qu’elles soient à la hauteur de ses oreilles. Ensuite, il récita l’Ouverture du Livre, et quand il eut fini, il dit “Amin” à haute voix