Hamlet's Dilemma

At first i didnt agree with Hamlet's decsion to not kill Claudius when he had the chance to do so but now that i have looked back at that decsion that he made i understand why he didnt do so at that time. Why would Hamlet want to go and kill Cladius while he is praying and asking God for forgivness for all the sins that he has commited which include the murder of his own brother which is Hamlet's father. I understood this decision that Hamlet made because he wants to go and kill Claudius while he is making a sin not while he is praying for frogiveness. I just think this shows how smart Hamlet is actually because he could have killed Claudius right there and no one could have known it was him that did it but he choose to wait and catch Claudius committing a sin and Hamlet would be able to put him on the spot for what he has done.