Mission (Lat., missio, ‘sending’). The sense of obligation in all religions to share their faith and practice with others, generally by persuasion, occasionally by coercion (see e.g. MARRANOS). The emphasis on mission varies from religion to religion. Thus in the case of Judaism, there was a strong practice of mission in the period of the second Temple. But after the failure of the two Jewish revolts, Judaism reconceived its vocation, and understood it to be the development of a holy community which is preparing the way for the coming of the messiah. Thus converts (who mainly come through marriage) are almost discouraged by being reminded of the burden of Torah-observation which they will have to carry.

Christianity, in contrast, believes that the messiah has come, that he is Jesus Christ, and that he has commanded his disciples to go out into all the world, proclaiming the good news (i.e. gospel), and baptizing all who believe. The 19th cent. was one of immense missionary expansion, somewhat contradicted by its own multiple divisions, often conducted with extreme rivalry and animosity. To overcome this, the Edinburgh Conference was convened in 1910, which became the origin of the modern ecumenical movement. Further Conferences (e.g., Jerusalem, 1928) were convened by the new International Missionary Council (IMC, 1921), which itself amalgamated with the World Council of Churches in 1961.

Islam is necessarily missionary (see DAʿWA) because it is derived from Muḥammad's absolute and unequivocal realization that for God to be God, there cannot be other than what he is. Thus other religions are assessed in terms of their description of God and attitude to him: on the one hand, there are ‘peoples of the Book’ (ahl al-Kitab), who have received their own Qurʾān, even though they have not preserved it without corruption, and they are the closest to God; on the other, there are those who are far from God, above all those who continue in any form of idolatry. There is to be ‘no compulsion in religion’ (Qurʾān 2. 257/6), but there is to be zeal in defending the honour of God.

It is sometimes felt that Eastern religions are less inclined to mission than Christianity and Islam, but that is only partially true. The process of rebirth will eventually bring all to the opportunity of mokṣa (release) without a necessity being imposed on Hindus to go out and accelerate the process. Nevertheless, in the 19th cent. societies were formed to propagate Hinduism (or rather, movements within the Hindu way); and in the 20th cent. some of the fastest growing new religious movements have been Hindu-based, attracting many converts.

In the case of Buddhism, the same consideration of rebirth obtains, but there was originally a far greater emphasis on making disciples. Within a few centuries, through the work of such figures as Bodhidharma and Kumārajīva, Buddhism had spread through China to Korea, and thence eventually to Japan. There have been a few societies formed with the intention of winning others to the Buddha's way, but these have not been so influential as have individuals in the West.