مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3053
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn ‘Abbas (رضي الله عنه) said: Sa'd bin 'Ubadah asked The Messenger of Allah (ﷺ) about a vow that his mother had made, and he told him to fulfil it.
Musnad Ahmad 3078Its isnad is saheeh, al-Bukhari (2761) and Muslim (1638)]