As the Church is moving towards its 21st century of existence, it is confronted by challenges it has never known before. This changing world demands self-reflection within the Church. It has to consider its place, identity and function, thereby giving rise to the exploration of its mission. In this article, the ecclesiology of Karl Barth is explored. By considering Barth's understanding of the Church's relationship with different parties such as God, other religions, those outside the Christian faith, the State and its own inner dynamics, the Church will be reminded of its missionary function in the world.