Nasai

462. Commentary:

➊ The Hanafis consider Witr to be obligatory (wajib), but their argument is based on narrations that are weak or that have the possibility of more than one meaning. In contrast, the authentic and definitive narrations, which have reached the level of tawatur, declare the obligation (fard) of five prayers and negate the obligation or wujub of any additional ones. Therefore, their view is not correct; rather, it should be called a confirmed Sunnah (sunnah mu’akkadah), which cannot be abandoned without a valid reason.

➋ The meaning of Witr in Arabic is “odd.” This prayer is called Witr considering the number of its rak‘ahs.

➌ The reasoning of Hudhayfah radi Allahu anhu is clear: the Messenger of Allah sallallahu alayhi wa sallam explicitly expressed the obligation of five prayers and described them as a necessary cause for entering Paradise. If Witr were obligatory, he would have mentioned it as well.

➍ «أَدْخَلَهُ اللہ الْجَنَّةَ» Because prayer is a means—and indeed a guarantee—for fulfilling other obligations and avoiding prohibitions, the reward for the one who prays is entry into Paradise, whether first or eventually.

➎ “If He wills, He will admit him to Paradise.” This is the perfect mercy of Allah, that He does not call to account for shortcomings in His rights.

1420. Commentary:
➊ It is understood that "Witr" is not obligatory (wajib) like the obligatory (fard) prayers, and the same applies to other Sunnah prayers, such as Tahiyyat al-Masjid, etc.
➋ Abandoning prayer is disbelief (kufr). Such a person is also under Allah's will; if He wills, He may punish him, or if He wills, He may forgive him. (Lā yus'alu 'ammā yaf'alu wa hum yus'alūn) [الأنبیاء:23] "Allah cannot be questioned about what He does, but they will be questioned."

425. Commentary:
➊ Abu Muhammad is a Companion. There is a difference of opinion regarding the determination of his name. Several names have been mentioned: Mas‘ud bin Aws, Zayd bin Asram, or Mas‘ud bin Zayd Sabi‘, or Qays bin ‘Amir Khawlani, or Mas‘ud bin Yazid, Sa‘d bin Aws, Qays bin ‘Ubayyah, etc. [الإصابة لابن حجر]
➋ The intent of the statement of ‘Ubadah radi Allahu anhu is that "Witr is not obligatory and compulsory like the five daily prayers." However, there is no difference regarding its being Sunnah and emphasized, as it is established that the Messenger of Allah sallallahu alayhi wa sallam would not leave Witr even during travel.
➌ For a complete and accepted prayer, one must know and act upon all the Sunnahs and obligations, i.e., performing the Sunnah complete ablution (wudu), at the legislated optimal time, with moderation in the pillars, and presence of heart, etc.
➍ The promises of Allah, which are mentioned in His Shari‘ah, are dependent only upon righteous deeds.
➎ Even without them, Allah may forgive whomever He wills or punish whomever He wills; no one can question Him. «لَا يُسْأَلُ عَمَّا يَفْعَلُ وَهُمْ يُسْأَلُونَ» [الأنبيا ء : 23]

Benefits and Issues:
➊ Only five prayers are obligatory. All others are supererogatory (nafl). However, some prayers are more strongly emphasized, while others are less so. Nevertheless, it is not permissible to be negligent in performing them either, because deficiencies in the obligatory (fard) prayers will be compensated by the supererogatory (nafl) prayers.

➋ What is meant by deficiency is either abandoning some prayers or not maintaining humility and submissiveness (khushu‘ and khudu‘) during the performance of prayer.

➌ Not giving the obligatory acts of the religion their due importance results in being deprived of Allah’s pleasure.

➍ Whoever performs prayer correctly and consistently will certainly enter Paradise, even if, due to some sins, he is sent to Hell for a period of time.

➎ Not giving importance to prayer can result in being deprived of forgiveness. That is why abandoning prayer has been declared as disbelief (kufr): just as a disbeliever cannot enter Paradise, similarly, one who abandons prayer will also be deserving of punishment.

Benefit:
From this hadith, it is understood that witr is not obligatory (wajib).