Surah al-Fajr, and the words of Allah the Exalted: "And by the ten nights"

Sayyiduna Jabir (may Allah be pleased with him) reported from the Prophet (peace and blessings be upon him) concerning this saying of Allah Almighty, Allah Almighty says: "And by the ten nights." The Prophet (peace and blessings be upon him) said: "This means the first ten days of Dhu al-Hijjah." "And by the even and the odd." The Prophet (peace and blessings be upon him) said: "The even means the day of Eid al-Adha, and the odd means the Day of Arafah."
Al-Bazzar and Ahmad recorded it, and the narrators of both are the narrators of the Sahih, except Ayyash bin Uqbah, and he is thiqah (trustworthy).

Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him) that he was asked about the even and the odd. He (peace and blessings be upon him) said: "Two days and a night: the Day of Arafah and the Day of Sacrifice, and the odd means the Night of Sacrifice, which is the night of Muzdalifah."
Tabarani recorded it within a long hadith; it contains a narrator, Wasil bin al-Sa'ib, who is matruk (abandoned).