This article presents the theological foundations for “religious engagement” from the perspective of Protestant theology. When Protestant churches engage on a global level, this is not an additional activity, but an expression of their ecclesial existence. The hope for the Kingdom of God and the conviction that humanity is created as imago dei motivate Protestant churches to engage in development cooperation. After presenting the theological foundations, the article gives examples from the work of the Lutheran World Federation and describes the challenges associated with “religious engagement”: the Christian hope for the world must be expressed in a contemporary way and the recognition of theological motives by non-religious actors is not always given. The appreciation of “citizenship” on a theological and political level could promote mutual understanding.