—al-Ḥākim, in his al-Arbaʿīn, transmits: “He performed Zuhr and ʿAsr, then mounted” (1); and Abū Nuʿaym, in his Mustakhraj on Muslim, narrates: “Whenever he was on a journey and the sun had declined, he would offer Zuhr and ʿAsr together, then set off” (2).

I heard our shaykh, the Imām ʿAbd al-ʿAzīz ibn ʿAbd Allāh ibn Bāz—may Allah have mercy on him—say: “This shows that when combining the prayers one should look at whether the departure is before the time or after it. If the departure is before the time, one combines with a delayed combination; if it is after the time, one combines with an advanced combination. That is preferable, yet whichever mode of combination he chooses is permissible, because the two prayer times have effectively become one. Thus, whether he prays at the beginning of that span or at its end, there is no harm. In the case of travel or illness, the time for Zuhr…"