From Sahih Muslim (Hadith 6172):
Abdullah b. Mas'ud reported Allah's Messenger (ﷺ) as saying:If I were to choose a bosom friend I would have definitely chosen Abu Bakr as my bosom friend, but he is my brother and my companion and Allah, the Exalted and Gliorious. has taken your brother and companion (meaning Prophet himself) as a friend
Reference: Muslim 6172