مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3643
Musnad of Abdullah bin Mas'ood
It was narrated that 'Abdullah (رضي الله عنه) said: The Messenger of Allah (ﷺ) said: 'Allah has angels who travel about the earth, conveying to me the salam of my ummah.”
Musnad Ahmad 3666This hadeeth was omitted from al-Usool; it appears in Atrafu