Why Hamlet delays killing Claudius?

In the Shakespearean play, Hamlet, the main character, Hamlet delays killing Claudius, his father's murderer, for a number of reasons. His main reason is his unsure mind about the ghost's apparition, then his pure mind of not sinning himself for killing him at prayer and lastly because he wants to catch Claudius at a time when he is killed, he has no chance of going to heaven. As the opening of the play, Hamlet learns …

…created many situations in the play Hamlet, which delayed Hamlet from killing Claudius. Throughout the play Hamlet failed three attempts in killing Claudius because first he is unsure, then when is sure, he sees Claudius begging for forgiveness, and at last he decides he wants to send Claudius to hell where he will suffer and that will be his revenge, he ends up waiting for a time where he can catch Claudius doing something immoral.