Romans 8:3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh.

After the fall of man, he became a slave to sin. Through his flesh he came under the dominion of sin, became a subject to it's power and consequences. I am sure that Adam did not know the devastating effect that sin will have over humanity and creations.

The killing of Abel, the pain of giving birth for women, the earthquake, the imbalances in the ecosystem etc. All of these were as a result of the fall of man. Unfortunately, man didn't recognize and do not know the effect of sin nor do they recognize the outworking of sin. The only way by which they would know it is by the introduction of the law.

Romans 5:20 So then, the law was introduced into God’s plan to bring the reality of human sinfulness out of hiding..."

The purpose of the law is to reveal sin and not to help humanity. It cannot serve beyond this, though the law is spiritual, it was not sent to help but to revealed our weaknesses. Without the law we would not have known there are certain things in us. 

What the law could not achieve, Jesus came and dealt with sin through the cross, now sin cannot exercise dominion over you because you are not under the law but under grace because of Christ. Now through the Holy Spirit you can live a life of victory forever, that's God's strength in you, the Holy Spirit.

Olanrewaju Niyi