Abu Dawud

There are two types of combining (jama‘): one is apparent (suri), the other is real (haqiqi). Performing the first prayer at its last time and the second prayer at its earliest time is called apparent combining (jama‘ suri), and performing one prayer during the time of the other by combining them is called real combining (jama‘ haqiqi). There are two forms of this: one is combining by advancing (jama‘ taqdim), the other is combining by delaying (jama‘ ta’khir). Combining by advancing (jama‘ taqdim) is to perform ‘Asr during the time of Zuhr and ‘Isha’ during the time of Maghrib, and combining by delaying (jama‘ ta’khir) is to perform Zuhr during the time of ‘Asr and Maghrib during the time of ‘Isha’. Both types of combining are established from the Messenger of Allah sallallahu alayhi wa sallam. Some people have said that what is meant by combining is the apparent combining (jama‘ suri), but the correct view is that what is meant is the real combining (jama‘ haqiqi), because the legislation of combining was for the sake of ease, and in the case of apparent combining (jama‘ suri), there is even more difficulty and hardship, since it is difficult to determine with precision the beginning and end of the prayer times.

2؎: From this it becomes clear that the concession of combining two prayers (jama‘ bayna al-salatayn) in one time is not restricted to the days of Hajj at ‘Arafah and Muzdalifah, because the Prophet sallallahu alayhi wa sallam also combined both prayers together at Tabuk.

3؎: From this it is understood that the continuity of travel is not a condition for combining two prayers (jama‘ bayna al-salatayn); even during a halt in the course of travel, combining two prayers is permissible.