Offering Tahajjud Salah After Witr Salah Offered With Isha
If one is sure that they are going to offer Tahajjud Salah on its proper time, then its better that one prays witr with that Tahajjud Salah, and can offer only two rakat Nafal Salah after Isha’s four Rakat Farz. But if not sure, then one can adopt this strategy of praying witr earlier with Isha and later on, if one gets a chance to offer Tahajjud, then with Tahajjud Salah as well. It is not a strict issue because it is a Nafal Salah to begin with, and rules and regulations are compratively lenient for Nafal rituals. Secondly, Prophet Muhammad (Sws) himself used to offer two rakat separate nafal Salah after Tahajjud Salah, since Tahajjud Salah was Farz on the Prophet (SWS).