The purpose of this essay is to study the problem of the human finitude and courage by ontological theology of Paul Tillich. It would be reconsidered the meaning of courage and the dynamic faith by understanding on correlation of being and God. Ontology is bone of the whole body theological thought of Tillich. It is the key to an understanding of the dynamics of the faith, and it is also connected to the courage. It can be said that the ontological element in the dynamics of the faith is the finitude. Finitude in awareness is anxiety. As finitude, anxiety is an ontological quality because it expresses finitude from inside. Anxiety is independent only on the threat of nonbeing. Since it is the purpose of this paper to develop the question of finitude and the solution of God implied in being, the ontological elements and categories are the center of the anxiety and courage. In other words, they are the finitude of being which drives us to the tension of faith, such as individualization and participation, form and dynamics, and freedom and destiny. The categories which is time, space, causality, and substance reveal their ontological character through their double relation to being and to nonbeing. Each category expresses not only a union of being and nonbeing but also a union of anxiety and courage. Tillich`s ontological analysis answers the question as to how courage is possible in the face of ineradicable anxiety. The answer to this question is furnished by revelation and by the existential decision which enters into faith in God. After all, the question of God is the question of the possibility of this courage. Tillich insists that many confusions in the doctrine of God and many apologetic weaknesses could be avoided if God were understood first of all as Being-itself or as the ground of being. Since God is the ground of being, he is the ground of the structure of being. The power of being is another way of expressing the same thing in a circumscribing phrase. Therefore, instead of saying that God is in the first place Being-itself, it is possible to say that he is the power of being in everything and above everything, the infinite power of being. Finally, the faith is a self-transcendent participation. We can say that the dynamics of the faith are elevated, when we could be enable to use symbols which point to the ground of reality.