From a human perspective, it is hard to imagine that sin would deserve such harsh punishment. However, most fail to understand just how bad sin is from God s perspective. Sin is a horrible violation against God and His creation. It destroys everything that is good. This is why God cannot allow sin into heaven.
Sin causes suffering and death.
Sin is the reason for the horror of hell. There is no sin in heaven. God cannot stand to look at sin, much less allow it in His presence in heaven. Only those who are righteous and sinless are allowed into heaven. Anything less than perfection is unacceptable.