مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3978
Musnad of Abdullah bin Mas'ood
It was narrated that Ibn Mas'ood said: I prayed two rak'ahs with the Messenger of Allah (ﷺ), two rak’ahs with Abu Bakr (رضي الله عنه) and two rak'ahs with 'Umar (رضي الله عنه).
Musnad Ahmad 4003Its isnad is saheeh, al-Bukhari (1657)]