It was narrated that `Asim bin Damrah as-Salooli said:
‘Ali (رضي الله عنه) said: Verily, Witr is not a must like your prescribed prayers, but the Messenger of Allah (ﷺ) prayed Witr, then he said: “Pray Witr, O people of the Qur`an. Pray Witr, for Allah is One and loves that which is odd numbered.”