مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3165
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn ‘Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) died and did not leave a will or any instruction [concerning who was to succeed him).
Musnad Ahmad 3189lts isnad is saheeh]