Raml began in the seventh Hijri year. The Messenger of Allah (ﷺ) returned from Hudaybiyyah in the sixth Hijri year without performing Umrah. In accordance with the Treaty of Hudaybiyyah, he returned the following year to perform Umrah. It was the month of Dhul-Qa‘dah. Some of the Companions had been afflicted with fever that year. Therefore, the polytheists of Makkah mocked the Muslims and began saying to one another, “A people are coming to you who have been weakened by the fever of Yathrib (Madinah).”[1] Upon hearing this, the Messenger of Allah (ﷺ) instructed the Companions (may Allah be pleased with them) to perform raml—that is, to jog with short steps, swaying the body and holding the chest out, in the manner of military forces in our time. The purpose was to make the polytheists understand that a believer is never weak. For the same purpose, along with raml, he also instructed them to perform idtiba—that is, to place the upper garment beneath the right armpit and leave the right shoulder uncovered. Since then, the rulings of raml and idtiba have remained in effect.
[1] - عن ابن عباس رضي الله عنهما قال :قدم رسول الله صلى الله عليه وسلم وأصحابه ، فقال المشركون : إنه يقدم عليكم قوم قد وهنتهم حمى يثرب ، فأمرهم النبي صلى الله عليه وسلم أن يرمـلوا في الأشواط الثلاثة .. وفــــــــــــي رواية زيادة : ارملوا ليرى المشركون قوتكم بخاري : 1602 ومسلم : 1262.