What is the main difference between earth and heaven -- assuming heaven actually exists? — R.M.
Let me assure you that heaven does exist! Heaven isn't something people dreamed up because they couldn't accept the idea that this life is all there is. Heaven is real -- and we know it because Jesus Christ came back from the grave to assure us it's real. Jesus said, "I am going there to prepare a place for you" (John 14:2).
The main difference between earth and heaven is that this world has been marred by sin -- but heaven has not. Heaven is perfect, because heaven (unlike earth) is free from sin's devastation. Never forget: Sin is like a crippling disease that corrupts and destroys everything it touches -- not just the human race, but all creation. Only at the end of the present age, the Bible says, will "the creation itself ... be liberated from its bondage to decay and brought into the glorious freedom (from sin) of the children of God" (Romans 8:21).
But heaven hasn't been touched by sin, nor will it ever be because heaven is the dwelling place of God, who is absolutely holy and without sin. This is why we must not only be forgiven, but we must be cleansed of our sins if we are to enter heaven. If you have trusted Jesus Christ as your Lord and Savior, the Bible says that "you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God" (1 Corinthians 6:11).
We can barely imagine what it would be like to live in a world that is totally free from all sin and sickness and death. But someday we'll live in a place like this: Heaven.