Musannaf Ibn Abi Shayba 3:4490

Hushaym narrated to us, he said: Juwaybir informed us, from al-Dahhak, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah is Witr (Odd/One) and He loves the Witr, so perform the Witr, O people of the Quran."