It was narrated that Abu Mijlaz said:

I asked Ibn ‘Abbas (رضي الله عنه) about Witr. He said: I heard the Messenger of Allah (ﷺ) say: “A rak’ah at the end of the night.” I asked Ibn ‘Umar and he said: I heard the Messenger of Allah (ﷺ) say: “A rak’ah at the end of the night.”