In the name of Allah, Most Gracious, Most Merciful.
All the praise and thanks is due to Allah, Subhanahu wata`ala. Peace and blessings be upon His Messenger.
There are many differences between combining (jama’) and shortening (qasar) prayers, including the following:
1. Definition
Qasar Solah is the shortening prayers the four-rak’ah prayers: Zuhur, ‘asar, and ‘Isha, turning it to a two rak’ahs when one is travelling (musafir) [on a good cause free of maksiat]. It is not applicable to Maghrib and Fajar Prayers.
Allah says:
“And when you (Muslims) travel in the land, there is no sin on you if you shorten As-Salah (the prayer)”
[Al-Nisa]
And the Prophet (peace and blessings of Allah be upon him) said: “The prayer when travelling is a two rak’ahs.”
[Narrated by al-Nasa’ie, 1420; classified as sahih by al-Albani in Sahih al-Nasa’ie]
The Prophet (sallallahu ‘alaihi wa sallam) said: “Allah has waived half the prayer for the traveller.”
[Narrated by al-Nasa’ie, 2275; classified as hasan by al-Albani in Sahih al-Nasa’ie]
Anas bin Malik (radiallahu’anhu) said: “We went out with the Prophet (sallallahu ‘alaihi wa sallam) from Madinah to Makkah, and we prayed two rak’ahs each time, until we came back to Madinah”.
[Narrated by al-Bukhari, 1081; Muslim, 693]
As for jama’ (combining) solat means the worshipper combine or join up two prayers, Zuhur and ‘Asar, or Maghrib and ‘Isha’, at the time of the earlier or later of the two solah [zuhur and ‘asar at zuhur or ‘asar; Maghrib and isya’ at maghrib or at isya’].
Anas ibn Malik (radiallahu’anhu) said: “The Prophet (sallallahu ‘alaihi wa sallam) joined Maghrib and ‘Isha’ prayers when travelling.”
[Al-Bukhari (1108)]
Mu’adz (radiallahu’anhu) said: We went out with the Messenger of Allah (sallallahu ‘alaihi wa sallam) on the campaign of Tabuk, and he used to pray Zuhur and ‘Asar together, and Maghrib and ‘Isha’ together.
[Muslim (706)]
It was narrated that Ibn ‘Abbas (radiallahu’anhu) said:
The Messenger of Allah (sallallaahu ‘alaihi wa sallam) joined Zuhur and ‘Asar, and Maghrib and ‘Isha’, in Madinah when there was no fear and no rain.
[Muslim (705)]
2. Ruling of Shari’e
The scholars unanimously agreed that shortening (qasar) the prayers is mustahab for the traveller (musafir) than offering them in full, because the Prophet (sallallaahu ‘alaihi wa sallam) shortened (qasar) prayers during all his journeys, and there is no sahih report that he offered the prayers in full [ the four rak’ah solah] whilst travelling.
Ibn ‘Umar (radiallahu`anhu) said: “I accompanied the Messenger of Allah (sallallaahu ‘alaihi wa sallam) and he did not do more than two rak’ahs [i.e the four rak’ahs solah] whilst travelling, and the same applies to Abu Bakar, ‘Umar and ‘Uthman (radiallahu`anhum)”.
[Al-Bukhari (1102)]
The Hanafis are of the view that it is obligatory for the traveller to shorten his prayers. But the correct view is that of the majority [the Hanbalis, Malikis and Shafi’es], that shortening (qasar) the prayers is Sunnah Mu’akkadah (a confirmed Sunnah), and that it is better (mustahab) than offering the prayers in full.
[See: al-Ijma’ by Ibn al-Mundhir (27); al-Mughni (1/382); al-Mawsu’ah al-Fiqhiyyah (27/274)]
Some scholars view that it is not permissible to combine prayers anywhere except in the case of the pilgrim in these two places, ‘Arafah and Muzdalifah.
The correct view is that of the majority of scholars, which is that it is permissible to combine (jama’) prayers if there is a valid situation and need for doing so, because it is proven that the Prophet (sallallaahu ‘alaihi wa sallam) did it in places other than ‘Arafah and Muzdalifah.
3. Reasons which make it permissible to jama’ and qasar prayers
The reasons which make it permissible to combine (jama’) prayers are broader than those which make it permissible to shorten (qasar) them.
Jama’ or combining prayers is permissible for the travellers and for the non-travellers if it is too difficult for him to offer every prayer on time, such as one who is sick, or if there is rain, or he is busy with some work that he cannot delay in order to pray, such as a student taking an exam or a doctor who is doing surgery and so on.
With regard to the qasar (shortening) prayers, it is only permissible when travelling on good cause not involving maksiyat.
Shaykh al-Islam Ibn Taymiyah (rahimahullah) said:
The reason for shortening (qasar) prayers is travelling only, and it is not permissible in situations other than travelling. As for combining (jama’) prayers, the basis for it is the necessity and valid situations. So if a person find it necessary and needs it he may jamak, or do both qasar and full-length prayers whilst travelling, and he may jamak prayers when it is raining and so on, or because of sickness and the like, and for other reasons, because the purpose behind it is to spare the ummah hardship.
[Majmu’ al-Fatawa (22/293)]
Shaykh Ibn ‘Uthaymeen said: Jamak (combining) prayers are broader in scope than shortening (qasar) them, i.e., the reasons for doing so are more numerous.
[Al-Liqa’ al-Shahri (60/11)]
And Allah knows best.
Shaykh al-Albani says:
'I say: As for this dislike, then even though it is devoid of evidence, it also
opposes the Sunnah which was narrated by the scholar of the Ummah,
Abdullaah bin 'Abbas -radiAllaah anhu.
Musa bin Salamah mentioned: 'We were with Ibn Abbas in Makkah and I said
to him: ‘When we are with you we pray four rakat prayers and when we return
to our temporary residences we pray two rakat prayers?' He answered: 'That is
the Sunnah of Abul-Qassim - sallAllaahu alayhi wa sallam.'’
Narrated by Ahmad with an authentic chain and it was also narrated in a
summarized form by Muslim, Abu 'Awaana and other than them. It has been
researched in 'al-Irwaa' (571).
Taken from 'Tamam al-Minnah' p.371 by Shaykh al-Albani