جامع الترمذي

Narrated Abu Hurairah: "We camped with the Messenger of Allah (ﷺ) at a place, and the people began passing by. The Messenger of Allah (ﷺ) would say: 'Who is this, O Abu Hurairah?' So I would say: 'So-and-so.' So he would say: 'What an excellent slave of Allah this is.' And he would say: 'Who is this?' So I would say: 'So-and-so.' So he would say: 'What a bad slave of Allah this is.' Until Khalid bin Al-Walid passed, so he said: 'Who is this?' So I said: 'This is Khalid bin Al-Walid.' He said: 'What an excellent slave of Allah is Khalid bin Al-Walid, a sword from among the swords of Allah.'"