4 – While on a journey the three four-unit prayers were left at their original number—two rakʿahs each—so they are the ones that are shortened from four to two. Maghrib, however, remained at three and was not shortened because it is the day’s witr; if one rakʿah were removed it would no longer be witr, and if two were removed only a single rakʿah would remain, which has no parallel. Fajr likewise is two rakʿahs, and were it reduced to one it would become a solitary rakʿah with no counterpart. Thus, by consensus, neither Maghrib nor Fajr is shortened.

5 – Shortening the prayer is a mercy from Allah to His servants, for the traveler is subject to hardship, fatigue, and weariness. Out of His kindness Allah relieved him of half the prayer and accepted from him the other half, so that he would not be deprived of the benefit of worship and thereby cut off from his Lord and from intimate supplication.

6 – The ḥadith shows that two rakʿahs are the obligatory form of the prayer in travel as long as the ruling of travel applies, whereas the resident prayer later received an addition. This underscores that the traveler should pray only in the shortened form, fearing that adding rakʿahs—since they are not intrinsic to the prayer—could invalidate it. This is among the evidences for those who hold shortening to be obligatory during travel, such as the Ẓāhirīs and the Ḥanafīs. It is reported that Imām Aḥmad hesitated to deem valid the prayer of one who performed four rakʿahs. Accordingly, shortening is an emphatically recommended Sunnah; when an act is so strongly urged, neglecting it becomes disliked. The stronger view, however, is that the prayer is called “shortened” (maqṣūrah) because this conforms to Allah’s words, “And when you travel through the land, there is no blame upon you for shortening the prayer” (al-Nisāʾ 4:101), and to the aḥādīth on the subject.

Shaykh al-Islām said: The sounder view is that the verse establishes a reduction both in the number of units and in the actions overall. He also said: Curtailing the prescribed four-rakʿah prayers to two is legislated by the Quran and the Sunnah, permissible by the consensus of the scholars, and has reached us from the Prophet ﷺ through mass-transmitted reports. The clearest opinion is that shortening is a Sunnah and that performing the prayer in full is disliked.

Ibn al-Qayyim said: It has never been authentically reported that the Prophet ﷺ ever completed a four-rakʿah prayer in full while traveling.