Hamlet did not murder Claudius as he did not want him to go to heaven. At first, he wasn’t sure about his uncle’s guilt and didn’t strive to stab an innocent man. Once Hamlet saw Claudius’ reaction to The Murder of Gonzago, all the doubts disappeared. Yet an opportunity to kill him appeared when Claudius was praying. Murdered in a sacred place with a prayer on one’s lips, a person would ascend to heaven. Hamlet could not let that happen.
Detailed answer:
In Act 3, Scene 3, Hamlet had an excellent opportunity to kill Claudius, but he delayed the act. Claudius was sitting on his knees with his back turned to Hamlet, and his eyes closed – completely defenseless. Nonetheless, he hesitated and left Claudius alone. Hamlet thought killing his uncle during the prayer, in a sacred place, will give him the chance to go to heaven:
It was unfair not only because Claudius would’ve escaped real punishment, but because Hamlet’s father didn’t have this chance. He died in his sleep, without repenting for his sins. The situation is ironic because Claudius was not genuinely praying. He was performing the act, but his mind was far from the prayer, though Hamlet did not know about that.
This scene shows that Hamlet’s problem was that he always thought about the aftermath. When he approached Claudius, he was inclined to kill him, but his excessive thinking prevented him from doing so.
These thoughts were coming from the beginning when the Ghost of Hamlet’s father visited him. The protagonist had a burden of doubt. Whether the spirit was good or evil and Claudius was guilty or innocent was a mystery. He was afraid to condemn his soul on danger, wishing to assure himself in Claudius’ guilt.
Later, Hamlet realized how much he loved his father; how much grief and sour was in his heart. It led him to the decision to kill the King. He promised to the Ghost to avenge him. However, the more he thought about this, the more doubts he had in his head. This hesitation was probably the reason for his delay in the murder of the King.
It may seem that Hamlet was weak and incapable of murder. Yet, he always impulsively acted unless he had a chance to think and analyze the situation. The scene Hamlet was confronting his mother is a good example. Overwhelmed with emotions, he killed Polonius, who was hiding behind the curtain. Similarly, Hamlet acted on adrenaline in Act 1, Scene 2, when he faced his mother’s death and felt the poison taking over his body. Being overcome with grief and pain, he finally killed Claudius. In other words, Hamlet is capable of murder, and his acts are based on emotional impulses.
Another reason for Hamlet’s decision was to preserve his character in the play. If he killed Claudius when he had a chance, he would prevent other deaths that would follow. The story would lose its meaning. Hamlet would no longer be a tragic character who met his death. Moreover, the King’s murder would make him a villain rather than a hero of the play. This situation resembles Shakespeare’s Macbeth, where the central character killed King Duncan while later was asleep. This act is considered heinous, and it would make Hamlet’s act heinous act as well.