If I omit the witr Salaah, is my Isha prayer still valid?
Your Isha Salah would be valid if the Witr Salah is ommitted. Witr is a separate Salah and has no connection with the Isha Salah. Since its time begins from after Isha and ends at break of dawn, many people chose to perform it at the end of their Isha Salah at night especially when they are not in the habit of waking up for Tahajjud Salaah.
If however one is habitual in performing Tahajjud Salaah then the best time for the Witr is after the Tahajjud is performed before the time of Fajr enters (that is before the break of dawn).
Witr Salah is not Fard, however due to the strict ruling regarding its performance (as evident from many traditions of the Prophet (S.A.S)), many jurists have considered it as being Wajib (essential).
Among these traditions is the hadith recorded by Imam Bukhari in his Saheeh, which states that Abdullah bin Umar (R.A) narrates that the Prophet (S.A.S) commanded them by saying , ‘make the last Salah of the night as Witr’. This being in the imperative tense was an order of the Prophet (S.A.S).
Similarly Imam Tirmizi has recorded the tradition in which the Prophet (S.A.S) said, ‘Witr is a right which is essential upon every Muslim’. Ibn Hibban and Hakim have both recorded this and have stated that it is in accordance to the conditions of Imam Bukhari and Muslim. Another tradition is that of Abu Saeed Khudri (R.A) who narrates that the Prophet (S.A.S) said, ‘whoever neglects his Witr or forgets it let him perform it in the morning or when he remembers it’ (Hakim has recorded it and has stated that this tradition fulfills the conditions of Imam Bukhari and Muslim and is Saheeh (sound)).
Imam Abu Dawood has also narrated the tradition of the Prophet (S.A.S) in which he said, ‘Witr is a right, whoever does not perform it is not from us’. ‘Witr is a right, whoever does not perform it is not from us’. ‘Witr is a right (Haqq), whoever does not perform it is not from us’. Hakim has also recorded this Hadith in his Mustadrak and has stated that it is Saheeh (sound)).
And Allah knows best.
Mufti Waseem Khan
This answer was collected from DarulUloomTT.net, which is operated under the supervision of Mufti Waseem Khan from Darul Uloom Trinidad and Tobago.