Ayesha, the wife of the Prophet (peace be upon him) reports: “When God ordained prayer for believers, every prayer was made in two rak’ahs, both in one’s hometown and during travel. It was later to continue as such during travel, but prayer in one’s place of residence was increased.”(Related by Al-Bukhari).
This Hadith suggests that in the early days of Islam, every obligatory prayer other than Maghrib was composed of two rak’ahs, but most scholars disagree, because it is in conflict with the Quranic verse that permits shortening prayers during travel. The verse implies that the longer prayer was established first and then reduced for travelers. Moreover, the nature of how prayer was made obligatory during the Prophet’s night journey suggests that making things easy was a paramount consideration. To move from a shorter to a longer version of prayers runs contrary to this because it is a move to what is harder.
Imam ibn Hajar provides an insight into how matters developed. He says that when the five daily prayers were made obligatory to Muslims at the time of the Prophet’s night journey, they were made two rak’ahs each except Maghrib, which is three rak’ahs. Then they were made four rak’ahs each, except Fajr in which the Quranic recitation is longer. Maghrib stayed in three rak’ahs because it is the one that makes the total number of rak’ahs an odd number. When the 4-rak’ah prayers were thus well established, they continued to be operative when people are in their places of residence but shortened when they are traveling.
Controversy among scholars on this issue of how prayers came to be short in travel and longer in residence is unimportant. However, it has become serious because some scholars are of the view that offering the short version in travel is obligatory. Their argument is that since prayers were originally of the shorter version and the increase in the place of residence is a later amendment, to offer the longer version in travel is wrong and unacceptable in the same way that it is unacceptable to offer prayer in more than four rak’ahs in normal conditions. Yet the overwhelming majority of scholars maintain that it is acceptable to offer prayers in the longer version, i.e. four rak’ahs, during travel, but to choose the shorter version is definitely preferable.
Scholars attach certain conditions to the concession of shortening prayer during travel. One of these is that the distance should be about 80 kilometers, but other scholars maintain that the concession applies to all travel, including a very short one. Another condition is the length of stay at one’s destination. Some schools of thought say that the traveler must not intend to stay more than four days at his destination. If he stays longer then he offers his prayers in the normal length. Other schools of thought increase this to 15 days. However, the point here is one of intention. If the traveler is unsure of the length of his stay in one place, as in the case of a person who intends to go back home shortly after he finishes his business, then he shortens his prayer throughout his stay, even if this extends into more than a month. The point is that throughout, the traveler remains unsure of how long he is staying.
A traveler begins shortening his prayers from the point when he leaves his hometown. Nowadays when we use trains and planes in travel, the concession becomes operative from the point when travel is initiated, i.e. when the train starts moving, or when we receive the boarding pass in the airport.