مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3536
Musnad of Abdullah bin Mas'ood
It was narrated that 'Abdullah bin Mas'ood (رضي الله عنه) said: The Messenger of Allah (ﷺ) said: “Whoever sees me in a dream has truly seen me, for the Shaitan cannot appear in my form."
Musnad Ahmad 3559Its is isnad is saheeh]