God created man a rational being, conferring on him the dignity of a person who can initiate and control his own actions. "God willed that man should be 'left in the hand of his own counsel,' so that he might of his own accord seek his Creator and freely attain his full and blessed perfection by cleaving to him."
Man is rational and therefore like God; he is created with free will and is master over his acts.
Source: Catechism of the Catholic Church (Vatican.va)