Musnad Ahmad 30:868

Sufyan ibn 'Uyaynah narrated to us, Isma'il ibn Abi Khalid said: On the authority of Qays, he said: Abu Hurayrah stayed with us in Kufa. He said: There was a kinship between him and our mawla (client) — Sufyan said: And they were the mawali (clients) of Ahmas — so the tribe of Ahmas gathered. Qays said: So we came to him to greet him — and Sufyan said once: So the tribe came to him — and my father said to him: "O Abu Hurayrah, these are your kinsmen; they have come to you to greet you, so narrate to them from the Messenger of Allah, may Allah bless him and grant him peace." He said: "Welcome to them and greetings. I accompanied the Messenger of Allah, may Allah bless him and grant him peace, for three years, and I was never more eager to memorize the hadith than I was during them, until I heard him say: 'By Allah, for one of you to take a rope, gather firewood on his back, eat from it, and give charity, is better for him than to come to a man whom Allah, the Exalted and Majestic, has enriched from His bounty, and ask him, whether he gives him or refuses him.'"