The word for emigration, hijra is derived from h-j-r means cutting oneself off from friendly or sociable relation, ceasing to speak to others, forsaking, abandoning, deserting, shunning or avoiding (4:34, 25:30, 74:5). It also means departure from the desert to the town or villages and vice versa. Its most common meaning is to forsake one’s own land and take up residence in another country. The Koran frequently uses the variations of the root kh-r-j to convey this sense (4:66, 8:30, 9:40, 60:1). It also has been interpreted to mean an emigration from the territory of unbelievers to the territory of believers for the sake of religion (4:97, 29:26). Technically, the term hijra has been used to designate the emigration of the Prophet and his early Companions from Mecca to Medina in 622 A.D. Its (hijra) various derivatives appear 31 times in the Koran, 16 of which refer to the emigration of Muslims from Mecca to Medina and the departure from home for the cause of God.
The first emigration of Muslims was to Abyssinia (Habasha, modern Ethiopia) when the Meccan persecution intensified, the Prophet instructed them to disperse in various directions. Upon their inquiry of where, exactly, to go, he advised them to set out for Abyssinia. The second but more consequential emigration was from Mecca to Medina.
It must be known that the classification of the suras or chapters of the Koran as Meccan and Medinan also takes account of changes in tone and terminology. While the pre-hijra verse use the vocative phrase “O you people” (ya ayyuha l-nas), post-hijra verse are often addressed to “O you who believe” (ya ayyuha lladhina amanu). Classical Koranic exegesis thus saw the hijra as the demarcation for major changes in the course of the umma’s development and for changing themes of the Koranic message. The Islamic calendar provides another indication of the decisive importance accorded to this event.
Early sources differ on whether the door of hijra i.e. the period in which emigration could be undertaken for religious reasons, was closed after the conquest of Mecca in 8/630 or whether it remained open indefinitely. The disagreement revolves around two sets of conflicting traditions. In one, the Prophet said, “There is no emigration after the conquest of Mecca.” In another, the Prophet is reported to have said, “The hijra will not come to an end as long as the infidels are fought.” The issue was so hotly debated in scholarly circles that both Abu Daud and Nisa’i included separate chapters in their hadith compilations.