Musannaf Ibn Abi Shayba 5:483

Ibn ‘Ulayyah narrated to us, from Habban ibn Yasar, from ‘Amr ibn Sa‘id, that a beggar asked Humayd ibn ‘Abd al-Rahman. Humayd said to him, "You are misguided," and it was as if he was angry. He ordered something for him, but the beggar considered it too little and refused to accept it. Humayd said to him, "Do as you wish; if you accept it, [well and good], otherwise we will give it to someone else." Then he said, "It used to be said: 'Turn away the beggar, even if it is with the equivalent of a sandgrouse’s head.'"