Why the Law, Then?

Since the law has only a shadow of the good things to come, and not the actual form of those realities, it can never perfect the worshipers by the same sacrifices they continually offer year after year.
(Hebrews 10:1-2 Holman Christian Standard Bible ©®)

Since the law Yahweh gave to the descendants of Abraham, Isaac and Jacob to transform them from the slaves of Egypt into the nation of God was only a shadow, should we discover what the Light was using to create the shadow? The law was given to Israel to prove their sin.

Why the law then? It was added because of transgressions until the Seed to whom the promise was made would come. The law was ordered through angels by means of a mediator. Now a mediator is not for just one person, but God is one. Is the law therefore contrary to God’s promises? Absolutely not! For if a law had been given that was able to give life, then righteousness would certainly be by the law. But the Scripture has imprisoned everything under sin’s power, so that the promise by faith in Jesus Christ might be given to those who believe. Before this faith came, we were confined under the law, imprisoned until the coming faith was revealed. The law, then, was our guardian until Christ, so that we could be justified by faith. But since that faith has come, we are no longer under a guardian, for you are all sons of God through faith in Christ Jesus.

For as many of you as have been baptized into Christ have put on Christ. There is no Jew or Greek, slave or free, male or female; for you are all one in Christ Jesus. And if you are Christ’s, then you are Abraham’s seed, heirs according to the promise. Now I say that as long as the heir is a child, he differs in no way from a slave, though he is the owner of everything. Instead, he is under guardians and stewards until the time set by his father. In the same way we also, when we were children, were in slavery under the elemental forces of the world. But when the completion of the time came, God sent His Son, born of a woman, born under the law, to redeem those under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of His Son into our hearts, crying, “Abba, Father!” So you are no longer a slave, but a son; and if a son, then an heir through God.
(Galatians 3:19-4:7 Holman Christian Standard Bible ©®)

The law was a shadow of the Spirit of Righteousness: the Holy Spirit, Whom He has sent to convert our hearts and minds to His ways. Be filled with Him, and manifest His Life and His character in everything you do and in everything that you refuse to do.