Though Frankenstein does not intend to be sinful, his actions are most certainly sinful. When he begins to study Agrippa, his father tells him to leave it alone. Frankenstein, in his arrogance, decides his father did not understand it, and he went on studying it. When he enters the university, he also seeks someone who will understand and help him. His professors, M. Krempe and M. Walden, encourage him and they become his mentors. This is when he begins to pursue in earnest his dream of reanimation.
It is here that Frankenstein tries to become God. In creating life out of dead body parts, without approval, he is “playing” God, and that is a sin. First, the ability to create life does not belong to him. It belongs to God. In addition, when the creature awakens, he cannot bear the sight of it and he runs away. He shuns the creature because of his appearance, and that is also a sin.
Finally, he is responsible for so many deaths. He knows the creature and its habits, and instead of telling the police where to find it, he pursues it himself. He wants to dispense punishment, which is not his place. If the creature is truly evil, God should punish him, not Frankenstein, who is, after all, his creator.