´Sufyan Ath-Thawri and others reported from Abu Ishaq, from Asim bin Damrah, that :` Ali said: "Al-Witr is not incumbent like the status of the obligatory prayers, but it is a Sunnah which Allah's Messenger practiced."
Hadith Referenceسنن ترمذي / أبواب الوتر / 454
Hadith Gradingزبیر علی زئی:(453۔454) إسناد ضعيف /د 1416، ن 1676، جه 1169, أبو إسحاق عنعن (تقديم :107) وروى أحمد (107/1 ح 842) بسند حسن عن على رضى الله عنه قال: ” ليس الوتر بحتم كالصلاة ولكنه سنة فلا تدعوه ۔۔۔۔ وقد أوتر رسول الله صلى الله عليه وسلم “ وھو يغني عنه
´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)."
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