As for their number, it is well known that there are five prayers: three of four rak‘ahs, one of three, and one of two. This applies when not travelling.

As for travel, the Messenger of Allah, peace and blessings be upon him, made nearly thirty journeys and would pray two rak‘ahs during his travels. No scholar has ever reported that he offered an obligatory prayer as four rak‘ahs while travelling. Even during the Farewell Pilgrimage, his last journey, he led the Muslims in prayers of two rak‘ahs each. This is common knowledge, widely transmitted through so many channels as to establish certainty, and unanimously reported by all his Companions and those who learned from them.

The hadith narrated by al-Dāraqutnī from ‘Ā’ishah, that “the Prophet, peace and blessings be upon him, would shorten his prayers while travelling and also offer them in full, and would break his fast while she would fast,” is false regarding offering the prayers in full, even if it is authentic regarding breaking the fast. It contradicts the widely transmitted, mass-attested accounts. Nor was this ever mentioned afterward.

How could this have happened, when the Prophet, peace and blessings be upon him, always led the obligatory prayers during his travels? The exception was once during the expedition to Tabūk, when he was delayed for a time while purifying himself. They appointed ‘Abd al-Rahmān ibn ‘Awf to lead, and the Prophet, peace and blessings be upon him, joined the prayer behind him for part of it.

Had he led them in four rak‘ahs while travelling, this would have been among the things they had the strongest reasons and greatest eagerness to report, since it would have departed from his consistent Sunnah and habitual practice—just as they reported that he sometimes combined two prayers. Since none of them reported such a thing, it is known with certainty that he did not do it.