This thesis deals with the research of the moral structure of man in the light of Christian revelation. The work begins with a speech about man, who was created in the image of God and whose dignity corresponds to acting according to that creation. We recognize this human dignity on several levels presented in this work. God revealed to man the moral law as well as the truth that man is capable of knowing this law and clinging to it as the supreme good and truth. As the bearer of the mark of the image of God by the gift of reason and freedom, man aspires to the knowledge of good and truth. In his freedom, as an essential constitution of his morality, he freely agrees with known truth and goodness and willingly directs himself towards them in his actions. In the conscience, man discovers the moral law that speaks of his moral constitution and that encourages him to choose good and reject evil. This discovery of the moral law reflects his dignity. The work also shows the drama of the sin by which man abused his freedom and thus wounded his reason, his dignity, his conscience and freedom itself, and thereby rejected the truth revealed to him about its meaning and ultimate goal. Accordingly, the thesis shows the renewal of man in Jesus Christ, in which the truth about man as the image of God is illuminated again, and in him he is enabled to act in accordance with his moral constitution.