of the earlier prayer. At other times one prayer may be moved into the time of the other, or the reverse, and all of this is permissible; for the root principle is that, when there is need, the two times merge, and advancing, delaying, or choosing the midpoint is governed by necessity and benefit.
5 – The hadith shows that the person who combines because of an excuse should choose whichever form—advancing or delaying—is easier for him, since the concession of combining was legislated only to remove hardship; he therefore adopts the option that is less burdensome.
6 – It also indicates that the rationale for combining is that the time of one prayer is legally treated as the time of the other. Hence, in delayed combination neither prayer is considered on-time while the other is a make-up; and in advanced combination the first prayer is offered in its own time, whereas the second is, in principle, prayed before its time—and a prayer performed before its appointed time is invalid.
7 – It establishes that travel is one of the excuses that permit combining.
8 – It confirms the permissibility of combining Zuhr with ʿAsr in one time period, and Maghrib with ʿIshāʾ in one time period. The narrator mentioned combining without qualification, which shows that both advanced and delayed combinations are allowed for Zuhr–ʿAsr and for Maghrib–ʿIshāʾ. Al-Tirmidhī’s report (550) gives the detail: “Whenever he set out before the sun had declined, he would delay Zuhr until he combined it with ʿAsr and pray them together; and if he set out after the sun had declined, he would bring ʿAsr forward to Zuhr and pray Zuhr and ʿAsr together.”
9 – Hadith no. 355 shows that combining Zuhr with ʿAsr and Maghrib with ʿIshāʾ is permissible even when the traveller is encamped and not pressing on with the journey.
10 – As for hadith no. 356, it indicates that the prayer is not to be shortened when the distance is less than four burud. One barīd equals four farsakhs, a farsakh equals three miles, and a mile is 1,600 metres; thus the minimum distance for shortening is approximately 77 km, as was clarified earlier.