Romans 8:3
Romans 8:33For what the law was powerless to do in that it was weakened by the flesh, God did by sending His own Son in the likeness of sinful man, as an offering for sin. He thus condemned sin in the flesh,
Watchtower commentary takes as confirming the inadequacy of the Mosaic Law for producing righteousness — God's solution was to send his Son in human form to bear the penalty for Adam's transgression. The verse is read as describing the corresponding-ransom mechanism: a perfect human life given in exchange for the perfect human life Adam forfeited.
explains why law-keeping does not work: the problem is not the Law's standard but the flesh's incapacity. The Law could not do what the cross did — condemn sin in the flesh of Christ. This decisively undermines any works-righteousness scheme: if the Law itself was incapable of producing righteousness because of human weakness, no system of organisational compliance can succeed where the Law failed. God's solution was incarnation and substitution, not a refined rule-system. 's earlier verdict — "you are not under law but under grace" — is the consequence: grace defeats sin precisely because law cannot.