Shortening the Prayer while traveling is a legal concession that portrays Islam’s tolerance and simplicity in matters of worship. Prophet Muhammad (peace and blessings be upon him) used to shorten his Prayer whenever he was on a journey.
Dr. Rajab Abu Maleeh, a Shari`ah consultant to IslamOnline.net, stated,
Scholars have discussed the virtue of either shortening (qasr) or completing Prayer (itmam) during travel. The majority of fuqaha are of the opinion that it is better to shorten Prayer if the travel distance amounts to the minimum level at which shortening Prayer is permissible. Some other fuqaha, however, deem it more appropriate to complete Prayer, since it is the default case.
However, we can safely say that completing Prayer is more appropriate in the following cases:
1. If the travel distance is less than the minimum distance at which shortening Prayer is permissible, according to the majority of fuqaha, which is approximately 80 kilometers. Though this distance is not established by clear proof from either the Qur’an or authentic Sunnah, it is determined by fuqaha according to a group of traditions that indicate it.
as regards the present question, thus, it is perhaps more appropriate to complete the Prayer since the mentioned travel distance is less than the minimum distance of shortening Prayer.
2. If the Muslim keeps in this state of travel for a long time, as is the case with the Muslim who keeps working in such a place for several years: having been determined to settle down as a worker in that place for a long time.
3. If both shortening and combining Prayer would prevent the Muslim from joining the congregational Prayer, from frequenting the masjids, and from performing the supererogatory Prayers performed before and after an obligatory Prayer), for such are educative acts of worship that a Muslim should not neglect. Indeed, this brings about a sense of joy and delight that could only be perceived by the Muslim who is used to frequent the masjid and to perform Prayer in congregation.
On the other hand, shortening Prayer is more appropriate in the following cases:
1. If the traveling Muslim who completes Prayers reproaches another traveling Muslim for shortening Prayer deeming that he or she does the right thing, by completing Prayer, and that the person who shortens Prayer is committing a mistake.
2. If the traveling person who completes Prayer during travel experiences a sense of self-conceit and superiority to others, deeming that he or she is nearer to Allah than they are or that they are far distanced from Allah than he or she is.
3. If the Muslim has never shortened Prayer during travel throughout his or her life, even if he or she suffers additional hardship and manifest exhaustion, since Almighty Allah likes that enacted concessions be observed. Imam Ahmad reported in his Musnad that the Prophet (peace be upon him) said, “Indeed, Allah likes that His rukhsahs (concessions) be observed just as He hates that sins be committed.”
Otherwise, both completing and shortening Prayer are equally permissible. However, the Muslim who completes Prayer wins a reward for frequenting the masjid, and for being eager to join congregational Prayer and to perform As-Sunan Ar-Rawatib (supererogatory acts of worship that were stressed and regularly performed by the Prophet).
Imam An-Nawawi stated in Al-Majmu`,
If the travel distance is three-day march, then it is preferable to shorten Prayer. It was reported from `Umran ibn Husayn that he said,
I performed pilgrimage in the company of the Prophet (peace be upon him), and he would offer Prayer two rak`ahs (shortening it), and I traveled in the company of Abu BakrAs-Siddiq,and he would offer Prayer two rak`ahs until he passed away. I then traveled in the company of `Umar ibnAl-Khattab,and he would offer Prayer two rak`ahs until he passed away. Afterwards, I traveled with `Uthman ibn`Affan,and he continued to offer Prayer two rak`ahs for six years, before he completed Prayer in Mina.
hence, imitation of the Prophet (peace and blessings be upon him) is preferable. However, if one avoids shortening Prayer and rather completes it, it is permissible: since it was reported from lady `A’ishah (may Allah be pleased with her) that she said,
I went out for `Umrah (Lesser Pilgrimage) in Ramadan with the Prophet (peace be upon him). Then, he broke the fast while I kept fasting, and he shortened Prayer while I completed it. So, I said to him, ‘O Messenger of Allah, you broke the fast while I kept fasting, and you shortened Prayer while I completed it.’ He then said, ‘Well done, `A’ishah.’
the case is so because it also involves a concession that is made permissible for the travelers, and likewise it is permissible for him or her to neglect it, just like wiping over the socks for ablution.
On the other hand, Sheikh Ibn Taymiyah (may Allah be merciful with him) stated in Majmu` Al-Fatawa,
Some fuqaha deem completion of Prayer better than shortening it, while some others deem shortening it better. Yet, they do not deem completion of it reprehensible; rather, they deem it more preponderant and that Prayer should only be shortened if one (traveling) has made the intention to do so in advance.
however, other fuqaha deem completion of Prayer impermissible, claiming that the sunnah is to shorten Prayer, and that it would be reprehensible to offer Prayer in four rak`ahs. They also claim that shortening Prayer is a regular practice of the Prophet, while combining Prayers (Jam`) is an occasional concession. Undoubtedly, this opinion is the closest to the Sunnah.