增壹阿含經 24.5.p29

24.5.p29

The five monks then called the Bhagavān “friend,” and he told the five monks, “Don’t say ‘friend’ to an unsurpassed Tathāgata, a completely and correctly awakened one. Why is that? I’m an unsurpassed arhat, a completely and correctly awakened one who has gained the good of immortality. You should focus your thoughts and listen to my teaching.”