Wherein Is The Law?
If the law cannot save, which is amply illustrated in this chapter, then what need is there that a law exist? It may seem to be of no value to anyone who is hearing these words of Paul.
But then Paul answers this objection by explaining that the law was added because of transgressions; that is, it did not take the place of the promise that was made 430 years before it, given to Abraham. It cannot supplant that promise nor make it of none effect.
The law was added to this promise to regulate the behavior of the people of God who would, without the law, no doubt have been even more sinful than they actually were. Being constrained by the law, their lives were to be holy before their Almighty God. They were to be true to holiness and righteousness. They were accountable to each and every law that God added to his promise. In other words, they became guilty before God as a results of the entrance of the law.
The law was for their good; for without the law of God, they would never have known anything about the life of holiness that would bring them success, joy, peace, and fellowship with the Father. They were constrained by the law to live a valuable and fruitful life that would bring God's blessings.
There must, then, be a reconciliation between God and man, because a man and his law cannot bring them together; it can only make men responsible before Him. Man is one, and with one there can be no mediator (verse 20). Man is one side of this disagreement (sin) between man and God, and God is one (the other one involved). We read, of course, in 1 Timothy 2:5 that Christ Jesus is the only mediator between God and men.
The law was given until the seed (Jesus Christ) came, to whom the promise was made (verse 19). This promise was not only made to Jesus Christ, but it was also accomplished in Him.
Now, if the law could give life (verse 21), then righteousness could be obtained and attained by the keeping of the law; but since the law is dead ("the letter killeth"), the conclusion must be that "all (are) under sin," and the promise "by faith of Jesus Christ might be given to them that believe." See Titus 3:5.