مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3666
Musnad of Abdullah bin Mas'ood
It was narrated that `Abdullah (رضي الله عنه) said: The Messenger Allah (ﷺ) said: "I have nothing to do with any close friendship. If I were to take a close friend. I would have taken Abu Bakr as a close friend. But your companion is the close friend of Allah, may He be glorified and exalted."
Musnad Ahmad 3689Its isnad is saheeh, Muslim (2383)]