´It was narrated that Ali, may Allah (SWT) be pleased with him, said:` "Witr is not essential like the obligatory prayers, but it is the sunnah of the Messenger of Allah (ﷺ)."
Related hadith on this topic
Explanation & Benefits
Hafiz Muhammad Ameen
1677. Commentary: Since Witr is a Sunnah of the Messenger of Allah (sallallahu alayhi wa sallam), which he never abandoned, therefore it is not permissible to abandon it without a valid excuse.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 1677