and unsupported by any evidence. They are mutually contradictory, and no sound limit can be set. For in most journeys, distances are not measured precisely, and the traveller’s pace varies. What the Prophet (peace and blessings be upon him) left unrestricted must be left unrestricted, and what he restricted must be restricted. Thus, a traveller may shorten his prayers on every journey. The same applies to all rulings connected with travel, including shortening prayers, praying on one’s mount, and wiping over leather socks. Anyone who divides journeys into short and long, assigns some rulings to one and others to the other, and makes them dependent on a long journey has no evidence that must be accepted. And Allah, Glorified and Exalted, knows best.
Shaykh al-Islām (may Allah have mercy on him) was asked:
If someone undertakes a journey of three days or three farsakhs, is he permitted to combine and shorten his prayers or not?
He answered:
Regarding combining and shortening prayers on a short journey, there are three views—indeed, four, or even five—in Ahmad’s school.