The dominance of the Eucharist ecclesiology in the middle of the previous century led to the underestimation of mission and missionary work. At the same time, it meant a certain animosity towards activism and social engagement. This paper shows the importance of the mission and how lack of mission in the negative way affects the Orthodox theology. Using historical examples, the author has shown that Orthodoxy, Eastern and Oriental, offers a solid and grounded theology of the mission. The mission is not just spreading the Christian message to people who know nothing of Christianity, but rather the developing awareness of the depth of the challenges of the global world. The Church facing the mission cannot remain indifferent to these challenges. Through this paper, we have shown that the mission of the very essence of the Church, is no less constitutive for the Church than the Eucharist, and that the mission is the implementation and continuation of Christ’s commandment in history, “… and teach all nations, baptizing them in the name of the Father, the Son, and the Holy Spirit” (Matt. 28:19).