مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3426
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) said: Shall I not tell you about the wudoo’ of the Messenger of Allah (ﷺ)? He called for water, then he started scooping with his right hand then pouring it over his left hand.
Musnad Ahmad 3450Its isnad is saheeh]