I heard the Messenger of Allah ﷺ when a man asked him about the Hajj at Arafah. He said, "The Hajj is the day of Arafah," or "Arafat. Whoever reaches the night of Jam before the dawn prayer has completed his Hajj. The days of Mina are three. Whoever hastens to leave in two days, there is no sin upon him, and whoever delays, there is no sin upon him."
حدثنا محمد بن جعفر حدثنا شعبة عن بكير بن عطاء قال سمعت
سمعت رسول الله ﷺ وسأله رجل عن الحج بعرفة فقال الحج يوم عرفة أو عرفات ومن أدرك ليلة جمع قبل صلاة الصبح فقد تم حجه أيام منى ثلاثة فمن تعجل في يومين فلا إثم عليه ومن تأخر فلا إثم عليه
Its chain of transmission is sahih. Bukayr bin Ataa Laythi Kufi is reliable, and his hadith is recorded by the group of scholars. The hadith was narrated by Tirmidhi 5/214, no. 2975, in the tafsir of Surah Baqarah, where he said, hasan sahih, and by Nasai 5/259, no. 3016, in the chapters on rites, on the obligation of standing at Arafah, and by Humaydi 2/399, no. 899, and by Tahawi in Sharh Maani al-Athar 2/209, and in Mushkil al-Athar 4/323.