Allah, The Mighty and Majestic, has prescribed a dispensation for shortening the prayer which has four unitsto a two-units prayer during travel, as a means to alleviate the hardship of travelling for His servants. The Messenger of Allah ﷺ shortened his prayer[s] while traveling; as likewise, so did all of his Companions (may Allah be pleased with them); like what is mentioned in this hadeeth, where ʿAbdullah ibn Abbaas(may Allah be pleased with them) reports that one day, the Prophet ﷺ stayed [at a location] for nineteen days and shortened the prayers which consist of four units, [which are:] Dhuhr, ʿAsr, and ʿIshaa’ ; and performed two prayer units [for each respectively] during that time. This happened in the year that the conquest of Makkah had occurred. In a narration [narrated] by Abu Daawood, on the authority of Ibn ‘Abbaas(may Allah be pleased with them), he relates that the Prophet ﷺ stayed in Makkah for seventeen days. And in [another] report also [narrated] by Abu Daawood from the hadeeth of ʿImraan ibn Husayn, [it is reported] that the Messenger of Allah ﷺ remained in Makkah for eighteen nights. And, yet, in another narration: it is reported that he ﷺ stayed fifteen. The scholars reconciled between these reports by noting that the report that states “nineteen” takes into account two days for arrival and departure [for travel]. And whoever said: “seventeen” omitted two days for arrival and departure. And whoever reported: “eighteen” left out one of the two days. As for the one who said: “fifteen”, it is possible that the narrator thought the original was seventeen, so he omitted the two days for arrival and departure. Then, Ibn ‘Abbaas(may Allah be pleased with them) said: ‘So when we travelled and remained for those [nineteen days], we shortened the prayers like the Messenger of Allah ﷺ. If our stay [while traveling] exceeded nineteen days, we would complete the prayer without shortening it.’ This is the view of Ibn ‘Abbaas(may Allah be pleased with them) and scholars differed on the view concerning this period of time, whether is it [i.e., 19 days] the maximum amount of time for shortening [the prayers], or not! It has been said that: if one intends to stay in a place indefinitely [i.e., an unspecified amount of time], it is incumbent upon him to perform the prayers in their entirety. And the traveller does not shorten the prayer if he intends to stay at a location for four days [or] more. If one remains in a place to fulfil his need[s], and does not have a resolve to stay therein; then he may shorten the prayer - even if the time of his stay is prolonged..