Most of the time...
Most of the time, they combine al-zuhr and al-`asr and [also] al-maghrib and al-`isha’, whether they are travelling or at home, whether they have an excuse [to combine] or without an excuse. Jam’ al-taqdim and jam’ al-ta’khir are equally valid for them [at all times]. As for the Hanafis, they have prohibited the combination [of prayers] absolutely except when combining at `Arafa and al-Muzdalifa.
[This is] despite the presence of numerous clear sahih (authentic traditions) which allow the combination, especially when travelling. However, despite the clear [traditions] they interpreted them to refer to an unintentional combination (al-jam’ al-suri). The invalidity of this [view] will become clear to you soon, God willing. As for the Shafi`is, Malikis and Hanbalis, they have allowed it (the combination) when travelling although there are differences between them.
Otherwise, they are not allowed to combine except for [genuine] excuses, for example, when there is rain, soil, sickness and fear. There are also differences between them on the conditions which constitute travelling which can be [termed]legal. Our proofs which we rely on between us and our God, the Almighty, on this and on other issues are the authentic [traditions] from our Imams, peace be upon them.
We shall argue with the masses (jumhur) by referring to their authentic traditions since they clearly point to what we claim. For us, sufficient proofs are [provided by] what the two Shaykhs have reported in the Sahihs. We present to you what Sahih Muslim has narrated in his Sahih in the chapter on the combination of prayers when at home. He says: “Yahya b. Yahya reported: `I read from Malik from b. Abu al-Zubayr from Sa`id b.
Jubayr from Ibn `Abbas [who] said: `The Prophet of God (S.A.W.) prayed the zuhr and `asr prayers together and [he also offered] the maghrib and `isha’ prayers together even though there was neither any fear nor was he travelling.'” Muslim also said: “And Abu Bakr b. Abi Shayba narrated to us that Sufyan b. `Uyayna reported from `Amr b. Dinar from Abu Sha`sha’ Jabir b.
Zayd from Ibn Abbas who said: `I prayed with the Prophet (PBUH) the eight [cycles] (of prayer) together and the seven [cycles] together.’ `Amr b.