The hadith of ‘Ali is a good (hasan) hadith.

Sufyan al-Thawri and others narrated from Abu Ishaq, from ‘Asim ibn Damrah, from ‘Ali, who said: The witr is not obligatory like the prescribed prayer, but it is a Sunnah which the Messenger of Allah, peace and blessings be upon him, established.

457 – Bundar narrated to us that, saying: ‘Abd al-Rahman ibn Mahdi narrated to us, from Sufyan.(1)

And this is more authentic than the hadith of Abu Bakr ibn ‘Ayyash.

And Mansur ibn al-Mu‘tamir narrated from Abu Ishaq similar to the narration of Abu Bakr ibn ‘Ayyash.

‌‌3 – Chapter: What has been reported regarding the disapproval of sleeping before the witr

458 – Abu Kurayb narrated to us, saying: Yahya ibn Zakariyya ibn Abi Za’idah(2) narrated to us, from Isra’il, from ‘Isa ibn Abi ‘Azzah, from al-Sha‘bi, from Abu Thawr al-Azdi, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings be upon him, commanded me to pray the witr before I sleep.(3)

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(1) In the edition of Shaykh Ahmad Shakir, there is an addition here: “from Abu Ishaq,” which is not found in our manuscripts, nor in the copy upon which al-‘Iraqi wrote his commentary. See the preceding hadith.
(2) As established in copies (B) and (L); in (A), (D), and (S): “Zakariyya ibn Abi Za’idah,” which is an error.
(3) A good (hasan) hadith, as the author said. Abu Thawr al-Azdi al-Huddani, from whom =