Are You Still Sinful? Why Do You Still Sin?

Are believers still sinful by nature? At salvation, what changed? Why do we still sin? Doesn’t God appear evil in the book of Job? I think James 2 is just talking about works after you’re saved. Why do you say the passage is about being justified (saved) by responding to God with faith?

“What is a reprobate mind?”

Why did God turn some over to a reprobate mind? Who are those people? What does that mean? How do we know when God is testing our faith? Can I donate my body to science, or does that offend God?