In his book (Re)union, Bruxy Cavey asks the question:

How much sin do you think it would be wise for God to let into heaven? What would be the acceptable level of sin for God to allow into the realm of eternal life? Should God allow 5 percent? Maybe 0.5 percent? Would 0.05 percent be okay?

The answer to that question has to be zero. When Olympic athletes are tested for performance-enhancing drugs, they fail the blood test if they have even a trace of these drugs. Their blood is either clean or not clean. The standard for passing is 0 percent of banned substances. They can't protest, "But I only have traces of the banned substances, so obviously I don't use them too much." The standard is perfection.

When someone wants to donate blood, the blood bank must ensure that the donor's blood is completely free from various things, like HIV. The person cannot protest, "But my blood is mostly HIV-free, and certainly I'm not doing as bad as some people who have full-blown AIDS, so what's the problem?" The standard has to be absolute purity, and for good reason.

The same is true for our relationship with God. God's standard for heaven must be sinless perfection, just as Adam and Eve were when they were first created. Just being a comparatively good person is not good enough. If God were to let us all into the eternal dimension with sin still a part of our spiritual makeup, we would pollute the realm of heaven, starting the whole mess of planet Earth all over again. So God bans sin from heaven. He quarantines the infection and the infected to a different realm. Hell is God's quarantine solution for people who prefer to hold on to their sin rather than accepting Christ's cleansing.