God knows everything, but this does not eliminate man’s responsibility to confess his sins. Failure to do so forfeits God’s practical forgiveness.
The soul that sins shall bear his iniquity. How does a man bear his iniquity? The answer is quite simple: by suffering the consequences of those sins.
Although the blood of Christ cleanseth from all sin, some things cannot merely be undone. With or without forgiveness, sin has certain consequences.
There are many things in this life that are not sinful in and of themselves, but when they are misused they can be deemed as sinful or harmful.
