He said, "The Messenger of Allah ﷺ commanded me to announce during the days of Mina that these are days of eating and drinking, so there is no fasting in them," meaning the days of Tashriq.
حدثنا روح حدثنا محمد بن أبي حميد المدني
قال أمرني رسول الله ﷺ أن أنادي أيام منى إنها أيام أكل وشرب فلا صوم فيها يعني أيام التشريق
Its isnad is daif, due to the weakness of Muhammad bin Abu Humayd. See 992, and the hadith appears in Majma al-Zawaid at 202 with this narration and the following narration at 1500. He attributed it to the Musnad, then said, "Bazzar also narrated it, and the narrators of all of them are the narrators of the Sahih." I do not have Bazzar's book at hand so I cannot verify its isnad, but as for the two isnads found here in the Musnad, their narrators are not the narrators of the Sahih. Rather, among them is Muhammad bin Abu Humayd al-Madani, who is daif, and neither of the two compilers of the Sahihayn included anything from him. Shawkani quoted the statement of the author of the Zawaid at 4:352 and did not comment on it critically, as though he was simply following him.