Shortened Prayer -Qasr
If one is on journey, the prayers are shortened. The Quran says: “When ye travel through the earth, there is no blame on you if ye shorten your prayers. (4:101)
The Sunnahs are dropped with the exception of Fajr prayer and the number of four Farz Raka’ats in the Zuhr, Asr and Isha prayers are reduced to two. The Witr of Isha prayers are retained.
in addition, the traveller is allowed to combine the Zuhr and Asr prayers and the Maghrib and Isha prayers. If he acts as the Imam, he shortens the prayer, while his followers who are not travellers complete the number of raka’ats but if the Imam is not on a journey, while his folawers are, the latter do not shorten the prayer.
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If a traveler stays in some place, then he may shorten his prayer as long as he is there. If he intends to stay in a place for a certain period ot time, but keeps delaying it for some reason, he may shorten his prayers, even for years.
According to some jurists, prayers may be shortened if the journey is for fifteen days and according to others, for nineteen days. A companion said The Prophet stayed, during some of his journeys for nineteen days and he prayed only two raka’at. If we stayed in a place for nineteen days, we would not pray the complete Salat. However. if we stayed longer than that, we would perfom the whole Salat.” (Bukhari)
There is a difference of opinion to the distance after which a traveler can shorten the prayer. According to some scholars. it is 48 miles.