Hamlet promises to the ghost of his father to kill the man who killed former King Hamlet. From that day, Hamlet has been trying to figure out a way to kill Claudius, his uncle, and present King of Denmark. It takes Hamlet a long time to kill him, speaking that he had at least one good chance to kill him, but he hesitates at every point he has to kill him except for the last. When he comes to a point where he could kill him, his conscience comes into play, which causes Hamlet to think twice.
His first instance of hesitation was during his meeting with the players, where he had the players add a part that reenacted the exact scenario that Hamlet was told by the ghost. By doing this, he could see the actions of Claudius while he saw the acted killing in front of his own eyes.
I’ll have the grounds
More relative than this. The play’s the thing
Wherein I’ll catch the conscience of the King.
-Hamlet, Act II, Scene ii 615-617
If the king went into an outrage, Hamlet would know that he was the killer of his father, therefor proving to himself that Claudius was indeed the killer, and the ghost wasn’t part of his imagination. Of course then again, if he didn’t have to prove it to himself, then he could have killed Claudius right away.
The play did come with a success. Claudius did show his disapproval of the play, proving to Hamlet that he was the killer.
Give me some light. Away!
-Claudius, Act III, Scene ii 275
But this leads to Hamlet’s second hesitation moment. While Claudius is trying to confess his sins, Hamlet sees a window of opportunity. He could kill Claudius with no one around and no one to witness, but Hamlet had second thoughts on the matter.
Now might I do it pat, now ‘a is a-praying,
And now I’ll do’t. And so ‘a goes to heaven,
And so am I revenged. That would be scanned.
A villain kills my father, and for that
I, his sole son, do this same villain send
Why, this is hire and salary, not revenge.
-Hamlet, Act III, Scene iii 73-79
Killing Claudius in the church would send him to heaven, or so Hamlet thought. But as the Catholic religion goes, full reconciliation of any sin includes giving back what was won and making amends for the sin committed. If Hamlet would have taken his second thought a little deeper, he could have successfully killed Claudius, upholding his vow to the ghost.
It is not until the fencing incident where Claudius is finally slain. But at this point, it wasn’t for the killing of King Hamlet, but for the poisoning of Gertrude, and the altered fencing sword with the poisoned end. As a result, Hamlet had two solid reasons to kill Claudius, even if others were around to witness it. The first thing was that he was dying anyway from the wound he suffered from the poisoned sword, so whatever he did wouldn’t matter. The second reason he could kill Claudius is that he was responsible for a death in the royal family, therefor punishable by death.
Hamlet’s hesitation to kill Claudius cost many others their lives. At least six lives could have been saved, maybe even seven, if Hamlet would have gotten the job done quickly and swiftly. Instead, he decided to prove everything to himself and wait for the perfect, ideal moment to slay Claudius. This resulted in seven deaths of people who weren’t even involved in the death of King Hamlet; hence, hesitation does not go without a price.