God made a Promise to Abraham in Genesis 22;17-18 that He would bless him and multiply his descendants like the stars in the heavens and like the sand on the seashore. And in his Seed meaning Christ, all the nations of earth be blessed because Abraham not only heard God’s voice but he also obeyed God’s voice. Therefore Abraham received righteousness because he believed God.
Now The Law was given by God through Moses (Exodus 20) and was added 430 years after the Promise because of sin. So the purpose of the law was to disclose and expose to mankind their guilt and to make mankind more conscious of sin. It was intended to be in effect until the Seed (the Descendant, the Heir) should come, to and concerning Whom the Promise had been made (Galatians 3:19). So the Law served as a trainer, a guardian and a guide to Christ that we might be justified (put in right standing with God) by and through faith (Galatians 3:24). Under the Law no one could be justified by it because no one could continue to live by all the commands written in the Book of the Law and to practice them. And that no person could be declared righteous and put in right standing with God through the Law (Galatians 3:10-11).
The scriptures say in St. John 1:17 that the Law was given by God through Moses, but Grace &Truth came by Jesus Christ. For God did what the Law could not do by sending His own Son in the likeness of sinful flesh and as an offering for sin. So that the righteous and just requirement of the Law might be fully met in us who live and move not in the ways of the flesh but in the ways of the Spirit. In other words being under the control of the Holy Spirit (Roman 8:3-4). Before Jesus came we were all imprisoned by sin. But now the inheritance, which was promised through faith in Jesus Christ might be given to those who believe. But before faith came we were perpetually guarded under the Law and kept in custody getting ready for the faith that was destined to be revealed (Galatians 3:22-23). In Christ Jesus you are all sons of God through faith. For as many as were baptized into Christ have put on Christ. There is now neither Jew or Greek, slave or free, male and female; for you are all one in Christ Jesus. And if you belong to Christ, then you are Abraham’s offspring and (spiritual) heirs according to the Promise.
Some Christians have a hard time with this because of traditional teaching and therefore they are still trying to keep the Law. But the scriptures are clear and say in Galatians 3:18 that the inheritance of the Promise is not based on keeping the Law but the Promise was given to Abraham as a free gift. And that the Law is not of faith and if you try to do the things prescribed in the Law then you will live by them and not by faith. We must understand that we are kept by the power of God and that we cannot keep ourselves. Jesus Christ purchased our freedom from the curse of the Law and it’s condemnation by becoming a curse for us. That the blessing Promised to Abraham might come upon the Gentiles. So that we through faith might receive the Promise of the Holy Spirit (Galatians 3:13-14)
There is therefore now no condemnation for those who are in Christ Jesus, who live and walk not after the dictates of the flesh, but after the dictates of the Spirit. For the law of the Spirit of life in Christ Jesus has made us free from the law of sin and death (Romans 8:1-2). For God did not send his Son into the world to judge (to reject, to condemn, to pass sentence on) the world, but that the world might find salvation and be made safe and sound through Him (St. John3:17). God- so rich is He in His mercy! Because of and in order to satisfy the great and wonderful and intense love with which He loved us, even when we were dead in sins, he made us alive together in fellowship and in union with Christ by His Grace (mercy which you did not deserve) that you are saved (Ephesians 2:4-5).
Some may say since we are no longer under the law but under grace that we should keep right on sinning since Jesus has paid the price for our past, present and future sins. The Apostle Paul taught against this wrong thinking in Romans 6 saying since we are dead to sin we should not live any longer in sin. The old man which is the old sin nature has been crucified with Christ that our body which is the instrument of sin might be made ineffective and inactive for evil, that we might no longer be the slaves of sin. Therefore don’t let sin rule as king in your short-lived bodies, to make you yield to its cravings and be subject to its lusts and evil passions. For sin does not have any dominion over you, since you are not under the Law but you are under Grace.