Is it permissible to combine the intentions of different prayers—such as the Sunnah of 'Isha, Dhuhr, 'Asr, and the Prayer of Need (Salat al-Hajah)—into a single prayer?

It is not permissible to combine the Sunnah of 'Isha and the Sunnah of Dhuhr or 'Asr with a single intention, for each of them is a regular prayer intended for its own sake and has a specific time. However, there is no objection to combining the Sunnah of 'Isha and the Salaat al-Hajah (Prayer of Need) with a single intention in two rak'ahs. Combining two acts of worship is permissible if one of them is not intended for its own sake, such as combining Tahiyyat al-Masjid (Greeting of the Mosque) with a fard (obligatory) prayer or another Sunnah prayer. But if both acts of worship are intended for their own sake, then it is not valid to combine them with a single intention.