As Christians, we should talk about life after death and Heaven and Hell because the Bible does. And if we really believe there is an afterlife and a final judgment, if we really believe that we will be held accountable for things that we say and do, then it will affect the way we live.
We cannot say something is true because we experienced it. Rather, we should say we know something is true because we find it in Scripture, which verifies our experience.
The word blasphemy speaks of a conscious denouncing and rejection of God. It is a defiant irreverence, a uniquely terrible sin of intentionally and openly speaking evil against God.
