He said:
We alighted at a camping-place along with God's messenger, and when the people began to pass, he was asking, "Who is this, Abu Huraira?" and I would tell him it was so and so. He would then say, "This is a good servant of God.' He would ask about another, and when I told him he was so and so he said, "This is a bad servant of God." This went on till Khalid b. al-Walid passed by, and when he asked who he was and I replied that he was Khalid b. al-Walid, he said, "Khalid b. al-Walid is a good servant of God; he is one of God's swords."
Tirmidhi transmitted it.