Suppose you sin by violating one of the Lord’s commands. Even if you are unaware of what you have done, you are guilty and will be punished for your sin.
All Scripture is inspired by God and is useful to teach us what is true and to make us realize what is wrong in our lives. It corrects us when we are wrong and teaches us to do what is right. God uses it to prepare and equip his people to do every good work.