Sam Storms, One Thing, Christian Focus, 2004, p.178.
Three texts in Revelation tell us who and what will be absent in heaven. In 21:4 we see that no tears of grief, no death or sorrow or pain will be present. In 21:8 we are assured that no one who is cowardly, lying, or unbelieving will be present, or murderers, or anything abominable, immoral, or idolatrous. And, as if to sum up, we are told in 21:27 that nothing unclean will be allowed to enter.
Sam Storms, One Thing, Christian Focus, 2004, p.178.