Abu Najih says that once someone asked Sayyiduna Ibn Umar (may Allah be pleased with them) about fasting on the day of Arafah. He replied: I performed Hajj with the Prophet (peace and blessings be upon him), but he did not fast on that day. I performed Hajj with Sayyiduna Abu Bakr, Sayyiduna Umar, and Sayyiduna Uthman (may Allah be pleased with them), but they also did not fast on that day. I neither fast on that day nor do I command it, nor do I forbid it.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5117
Hadith Gradingحکم دارالسلام:حديث صحيح بطرقه وشواهده .