Musnad Ahmad 262:5

Muhammad ibn Ja'far narrated to us, he said: Sa'id narrated to us, from Qatadah, from Sulayman ibn Yasar, from Hamzah al-Aslami, that he saw a man upon a dark-colored camel following the baggage of the people in Mina, while the Prophet of Allah, peace and blessings of Allah be upon him, was witnessing, and the man was saying: "Do not fast these days, for they are days of eating and drinking." Qatadah said: It was mentioned to us that that caller was Bilal.