Why the difference between OT "Law" and NT "Grace"?
The Torah, or Law, as rendered in most Bibles, never was, is not now, nor ever will be a salvation issue. There is only one salvation issue: the Messiah sent by God to be the perfect Passover Lamb, slain for our sins and salvation as a gift of God by grace through faith in His atoning death and resurrection. The Hebrew word Torah means "teachings and instructions."
Moses received this body of directives from God himself on Mt. Sinai after the Almighty, at His own initiative, supernaturally delivered the children of Israel from bondage in Egypt and through the Red Sea until they stood on the far shores a totally free people for the first time in 400 years. It was to this multitude of free people that God gave the Torah, instructions on how to live a godly lifestyle so that they would not return to slavery.
The experience of the children of Israel provides a pattern for our own experience as born-again believers in the Messiah of Israel. We were each born into the slavery of sin and were saved from it when God mercifully sought us and delivered us through the blood of His Son. He led us through the waters of baptism and now expects us to study and obey His Word so that we might live in freedom and not return to the bondage of our past life. Each of us is born into the slavery of sin but delivered from it through the blood of Jesus Christ.
Some proclaim that, "the Law has been done away with." It is the "curse of the Law," that has been done away with according to Paul's teaching in Galatians 3. Since the Scripture teaches that the "Law" only condemns law-breakers, why should any disciple of the Lord who desires to follow Him be anti-Law? If we seek to love Him with all our heart and soul and to live in obedience to His Word, there should be no controversy regarding the commandments He instructs us to follow. "If you love Me, keep My commandments," Jesus said in John 14:15.
It behooves the disciple of the Lord to study His Word, all of it, and to live an obedient life, for obedience is better than sacrifice (1 Samuel 15:22).