No one was ever saved by obedience to the Law. That's because upholding the covenant of the Law is impossible. Those like King David, who realized this, gave up on the idea that they could keep the covenant, and instead simply trusted God to do what He promised--even when they couldn't see how it would happen.

Everything in the Hebrew scriptures of the Old Testament points to this. All of it is designed to communicate about the Lord Jesus Christ. The covenants established in the Hebrew scriptures all required blood. This new covenant is no different. Life is on the line.