It is a theme that resounds from the pages of the Old Testament and nowhere more so than in Leviticus 5. The point is made repeatedly, if you violate the command of the Lord, whether you know it or not, you are responsible. There are no excuses. Even ignorance is no excuse. Ignorance or not, guilt applies and remains.
Obviously, a person ignorant of his transgression would not offer a sacrifice to secure atonement for his sin. But once he became apprised of the guilt, the sacrifice would have to come – and was owed even in ignorance.
Old Testament Bible scholar, R.K. Harrison, puts it like this: To fulfil one’s obligations as a member of a holy nation one must aim at being blameless, otherwise reproach will fall upon the people of God. Saint Paul professed to have as his aim a clear conscience towards God and men (Acts 24:16), and to avoid putting any obstacle in anyone’s way (2 Cor. 6:3). Thus he urged believers not to give offence to people in such a manner that they would not be saved (1 Cor. 10:32–33), thereby bringing blame upon the Christian ministry. In Philippians 2:14 Paul establishes an ideal of purity for the believer, urging such a person to be blameless and innocent as a child of God in an evil and perverse world. This can only be achieved when the individual holds fast to the living Word.
And that, of course, means we must know the will of God, and therefore know that Word.