Umm al-Fadl bint al-Harith (may Allah be pleased with her) narrates that some people disputed in her presence on the Day of Arafah about the Messenger of Allah (peace and blessings be upon him). Some of them said: He is fasting, and some of them said: He is not fasting. So Umm al-Fadl (may Allah be pleased with her) sent him a cup of milk while he was standing at Arafah on a camel, and he drank it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8384
Sayyidah Maymunah (may Allah be pleased with her) narrates that the people were in doubt about the fasting of the Messenger of Allah (peace and blessings be upon him) on the Day of Arafah, so Sayyidah Maymunah (may Allah be pleased with her) sent milk to the Messenger of Allah (peace and blessings be upon him) while he (peace and blessings be upon him) was standing at the place of standing (mawqif), and he (peace and blessings be upon him) drank from it while the people were watching.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8386
Sa'id bin Jubayr (may Allah have mercy on him) narrates: I came to Ibn Abbas (may Allah be pleased with them both) while he was eating a pomegranate at Arafah, and he narrated that the Messenger of Allah (peace and blessings be upon him) "did not fast at Arafah."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8387
Ayyub narrates from Ikrimah (may Allah have mercy on him) that Ibn Abbas (may Allah be pleased with them both) did not fast at Arafat. A pomegranate was brought to him and he ate it, and he said: Umm al-Fadl (may Allah be pleased with her) narrated to me that the Messenger of Allah (peace and blessings be upon him) did not fast at Arafat; Umm al-Fadl (may Allah be pleased with her) brought him milk, and he (peace and blessings be upon him) drank it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8388
Ikrimah (may Allah have mercy on him) narrates: We were with Abu Hurayrah (may Allah be pleased with him) in his house, and he narrated to us that the Messenger of Allah (peace and blessings be upon him) "forbade fasting on the Day of Arafah at Arafat."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8389
Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates: "The Messenger of Allah (peace and blessings be upon him) forbade fasting on the Day of Arafah at Arafat."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8390
Talhah bin Ubaydullah bin Kariz (may Allah have mercy on him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "The best supplication is the supplication of the Day of Arafah, and the best of what I and the prophets before me have said is 'La ilaha illallahu wahdahu la sharika lah' (There is no god but Allah, He is alone, He has no partner)."
This is mursal (the Successor narrates directly from the Prophet without naming the Companion).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8391