Of course it never was. We may well be children of God, but we still possess the old nature of sin. Indwelling sin is a continuing reality in the Christian life. If we try to live by the Law we find that the Law only promotes rebellion. For what I do is not the good I want to do.
Law only promotes rebellion.
The ultimate purpose of God's act of salvation was to gather to himself a people set apart for Him, a people set apart to live a life well-pleasing to Him, to the praise of His glory. The Law was not meant to achieve this end, either before or after conversion. The Law, in fact, promotes a way of salvation that is actually apart from the Law. It does not promote the way of obedience, but rather the way of grace through faith. The old nature that was our master, springing to life at every command of God, enslaving us to sin, no longer reigns.