Tirmidhi

1:
The summary of these two hadiths and other hadiths narrated in this chapter is that it depends upon the individual:
If he is fully certain that he will wake up in the last part of the night, then he should not perform the witr prayer after ‘Isha or before sleeping, but rather perform it in the last part of the night.
And if he does not have such certainty, then he should perform it after ‘Isha, before going to sleep.
There is flexibility in every aspect regarding this issue.

Hadith Commentary:
In other narrations, it is mentioned that the Prophet (sallallahu alayhi wa sallam) performed the witr prayer (salah al-witr) at the beginning of the night, in the middle of the night, and also at the end of the night.
Thus, it is established from him that performing witr any time after the ‘Isha prayer until before true dawn (subh sadiq) is permissible.
Hafiz Ibn Hajar (rahimahullah) has written that in different circumstances, the Prophet (sallallahu alayhi wa sallam) performed witr at different times.
Most likely, in times of difficulty or illness, he would perform it at the beginning of the night, and while traveling, in the middle of the night. However, his general practice was to perform it at the end of the night (Tafheem al-Bukhari).
The Messenger of Allah (sallallahu alayhi wa sallam) declared it permissible for the ummah, for their ease, to perform witr at any time during the night after ‘Isha, whenever possible.

Hadith Commentary:
(1)
The Messenger of Allah (sallallahu alayhi wa sallam) performed the Witr prayer at different times on different occasions, considering various circumstances. Perhaps during hardship and illness, he performed it at the beginning of the night; while traveling, in the middle of the night; whereas his general practice was to perform it at the end of the night.

In one narration from Aisha (radi Allahu anha), there is further clarification that the Messenger of Allah (sallallahu alayhi wa sallam) performed the Witr prayer in every part of the night—that is, at the beginning, in the middle, and at the end of the night—but ultimately, its performance reached the time of Sahar (pre-dawn).

In a narration from Jami‘ at-Tirmidhi, it is stated that when he passed away, he used to perform the Witr prayer at the end of the night.
(Jami‘ at-Tirmidhi, al-Witr, Hadith: 456)

By "the end of the night" is meant the beginning of Fajr.
As is made clear by a narration from Sahih Ibn Khuzaymah.
(Fath al-Bari: 2/627, 628)

However, for the ease of the Ummah, it has been declared permissible to perform the Witr prayer after ‘Isha at any time possible.

(2)
Shah Waliullah Muhaddith Dehlawi (rahimahullah) writes in Sharh Tarajim Bukhari:

The hadith of Aisha (radi Allahu anha) has two meanings:
٭ The Messenger of Allah (sallallahu alayhi wa sallam) in the last part of his life used to perform the Witr prayer at the time of Sahar, and he maintained this practice until he passed away. Before this, it was his practice to perform the Witr prayer after ‘Isha during all parts of the night.
٭ The second interpretation is that the final limit for the time of Witr is until Sahar; it should not be performed beyond this.

Hadith Commentary: Benefits and Issues: The last time for Witr is the time of suhoor (pre-dawn), and before this, it can be performed at any time after the 'Isha prayer. The Prophet (sallallahu alayhi wa sallam) practiced this in every part of the night for the ease of the Ummah. And in the last period of his life, the Prophet (sallallahu alayhi wa sallam) used to perform Witr in the last part of the night.

1435. Commentary: The time for the Witr prayer is until midnight. And the Witr of the pre-dawn (before true dawn) is until the time of sahar (just before true dawn).

Benefits and Issues:

➊
The time for Witr is after Tahajjud.
The fact that Witr is performed in every part of the night proves that Tahajjud can also be performed in every part of the night.

➋
The predominant practice of the Messenger of Allah (sallallahu alayhi wa sallam) was to wake up in the latter half of the night.
Aishah (radi Allahu anha) said:
The Messenger of Allah (sallallahu alayhi wa sallam) would sleep in the first part of the night and would get up in the last part to perform prayer.
Then he would rest on his bed.
When the mu’adhdhin would call the adhan, he would quickly get up.
...
(Sahih al-Bukhari, Kitab al-Tahajjud, Chapter: Whoever Sleeps at the Beginning of the Night and Revives Its End, Hadith: 1146)
This is most likely the situation mentioned in this blessed hadith:
“The most beloved prayer to Allah is the prayer of Dawud (alayhis salam),
and the most beloved fast to Allah is the fast of Dawud (alayhis salam).
He would sleep half the night,
then stand (in prayer) for a third of it,
then sleep for a sixth of it.
And he would fast one day and not fast the next.”
(Sahih al-Bukhari, Kitab al-Tahajjud, Chapter: Whoever Sleeps at the Time of Sahar, Hadith: 1131)

➌
The practice that the Messenger of Allah (sallallahu alayhi wa sallam) adopted in the last part of his life was to perform prayer until true dawn (subh sadiq); however, after performing the Sunnah prayers of Fajr, he would lie down for a short while.

Takhrij:
«أخرجه البخاري، الوتر، باب ساعات الوتر، حديث:996، ومسلم، صلاة المسافرين، باب صلاة الليل، حديث:745.»©Explanation:
➊ This hadith proves that the Prophet sallallahu alayhi wa sallam performed the witr prayer at the beginning, middle, and last part of the night.
➋ The time for witr begins after the ‘Isha prayer and lasts until the break of dawn (fajr). Those who are accustomed to performing the tahajjud prayer should perform witr in the last part of the night, and those who are unable to wake up at the time of suhoor should perform it after the ‘Isha prayer.
➌ If, due to some necessity or excuse, one is unable to perform witr at its proper time, then it should be performed until the congregation for fajr is established. However, if one sleeps or forgets, then whenever he wakes up or remembers, he should perform it, because it is permissible to make up missed prayers (qada) during disliked times. Another opinion in this regard is that if witr is not performed at its proper time, then there is no need to perform it later; some narrations support this view as well, but according to some scholars, this ruling is for those who deliberately abandon witr.
See: (Hashiyah Tirmidhi, Ahmad Muhammad Shakir: 2/333). Also, in some narrations, it is mentioned that if ever, due to sleep or illness, the Prophet sallallahu alayhi wa sallam missed qiyam al-layl, he would perform twelve (12) rak‘ahs after sunrise.
See: (Sahih Muslim, Salat al-Musafirin, Hadith: 746). Based on this hadith, the opinion of most scholars is that whoever misses witr should make it up in an even number; that is, instead of one witr, he should perform two rak‘ahs, and instead of three witr, he should perform four rak‘ahs.
However, in our view, this is necessary for the one who is accustomed to performing tahajjud prayer; for the common person, making up the missed witr in the form of witr itself seems more appropriate.
And Allah knows best.

Benefit:
In this hadith, the time for the Witr prayer is mentioned: it can be performed at any part of the night, from after the performance of the ‘Isha prayer until the call to prayer (adhan) of Fajr.