Mishkat al-Masabih #743

Nafi‘ said that when Ibn ‘Umar began prayer he said the takbir and raised his hands; when he bowed he raised his hands; when he said, “God listens to him who praises Him” he raised his hands; and when he got up at the end of two rak'as he raised his hands. Ibn ‘Umar traced that back to the Prophet. Bukhari transmitted it.