Musannaf Ibn Abi Shaybah 7035 — Those who said: witr is obligatory

Sayyiduna Kharijah bin Hudhafah al-Adawi (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) came out for the Fajr prayer and said: "Allah Almighty has granted you in the night an additional prayer which is better than red camels." We asked: "O Messenger of Allah, which prayer is that?" He said: "It is witr, which is prayed between Isha and the break of dawn."