Even before God gave His covenant to Abraham He was judging the world by His moral law. And the people who were not given the Abrahamic covenant were still held accountable to God's moral law. At Mt. Sinai, God gave a covenant to the people He had chosen to be His own. The non-Jews were still held accountable to God's moral law, although they had no covenant with God. So God has always had a moral law separate and apart from the covenants He made with His people. This moral law is a reflection of God's holy nature.
Humankind has always been subject to the moral law of God, and those who obeyed showed "that the requirements of the law are written on their hearts, their consciousness also bearing witness, and their thoughts now accusing, now even defending them" (Rom. 2:15). However, God wanted a love-relationship with His people. He wanted a covenanted people for Himself. And so He chose one small nation on the face of the earth through whom He would teach the world about Himself.
God gave the Ten Commandments to this small nation. These Ten Commandments are explicitly referred to as the terms of the covenant that God gave to Moses. "Then the Lord said to Moses, 'Write down these words, for in accordance with these words I have made a covenant with you and with Israel ... And <Moses> wrote on the tablets the words of the covenant - the Ten Commandments'" (Ex. 34:27-28). The Ten Commandments were a full but succinct expression of God's moral law, delivered within a limited cultural context.
The Law of Moses was a judicial law, given by God to apply the principles of the Ten Commandments to the daily life of Israel. Paul said that the Law of Moses was "holy, righteous, and good" (Rom. 7:12). Included in the Law of Moses were many ceremonial laws which taught God's moral truths in picture form. They illustrated how sin separates us from God, and that justice demands a penalty for our sins.
Nevertheless, the Law of Moses was a judicial law, and human judges tried the cases and imposed the penalties. The Law protected and enforced the covenant by punishing the guilty and providing restitution to the victim. But human judges could not read the intention of the heart. They could only judge by outward action. For this reason, the Law could only enforce outward obedience to the covenant (the Ten Commandments). The Law could not force a man to love God in his heart. The Law could not force a woman to love her husband in her heart. The Law could not prevent, let alone punish, covetousness of the heart.
Paul said that law was not given for the righteous man, but for the unrighteous man (1 Tim. 1:9). The unrighteous man had to be constrained by the Law to outwardly obey the covenant (the Ten Commandments). The righteous man was compelled by his love of God to an inward as well as outward obedience.
The Law of Moses revealed sin in its fullness. It made sin utterly sinful. But it could not make people faithful to a love-relationship, a covenant with God. And so Paul tells us that there were two covenants, the covenant made at Mt. Sinai, and the covenant made with Abraham (Gal. 3:15-25; 4:21-31). The Abrahamic covenant was a love-relationship. The Mt. Sinai covenant was a law-relationship, in so far as it had to be enforced by the Law of Moses.
The righteous Israelites in the Old Testament trusted God and loved Him because He had promised to take care of them. God proved Himself by rescuing them from slavery and forging them into a nation. The righteous Jew responded by an inward as well as outward obedience to the Ten Commandments. In the New Testament, God proved Himself with the greatest saving deed of all. He gave His own Son to die for our sins, and to pay the penalty of death demanded by the Law of Moses. For death is what the Law would have required if the judges could have read our hearts. The righteous believer today responds to Christ's sacrifice by obeying God's moral law from the heart.
Jesus died for the Jews who had broken the Ten Commandments, that is, the old covenant. Since the Ten Commandments were a full but succinct expression of God's moral law, when Jesus paid the judicial penalty of the Law, He also paid for the sins of those who were not under the Law. But here we begin to see that this sacrifice of Jesus is much more than a legal act that satisfies the judicial penalty of the Law. For Jesus established a new covenant made in His blood, a relationship based not on the fear of punishment, but on the love and gratitude we feel toward God (1 John 4:18).
The new covenant is not new in time. It was given to Abraham as we recall. The new covenant is new in its completion in Christ. God's moral demands have always been the same to those within the covenant and to those without the covenant. We must love God and we must love our neighbor as ourself. But the reference point is new. Once the righteous Jew had responded with love to the God who rescued His people from slavery. ("I am the Lord your God who brought you out of Egypt..." is the prologue to the Ten Commandments.) Now the righteous believer responds in love to the One who rescued her from death by dying in her place.
Imagine the reaction of the believing Jew who had been released from the penalty of the Law of Moses (Jesus having died in his place). For the believing Jew, this must have meant that he was freed from the penalty of God's law altogether. Certainly, Paul taught that the believer was not under law but under grace (Rom. 6:14). It was this unearned gift of God that called the believing Jew into a love-relationship with God. The Jew who put his faith in his obedience to the Law of Moses did not understand the incomparable gift that God had given him. Worse yet, he was self-righteous. He could not love other people as Jesus had loved him, because he didn't realize the depths of Christ's love.
The believer today is faced with a similar challenge. Can we believe that Jesus loved us so much that He died in our place? Can we believe that God has freed us from the penalty of His law? Do we look for a new law to replace the Law of Moses, or do we humbly come before God as the recipients of His free gift of forgiveness? Our answers to these questions will determine the depth of relationship we have with our holy God. Our answers will determine how much love we really have to give to others. Does that mean that the Christian can go on sinning so that grace may abound? Is it enough that Christ paid the judicial penalty of the Law of Moses? By no means! Christ died so that we might enter into a love-relationship with God. If we accept Jesus' sacrifice for ourself, we must respond with a grateful obedience. "A new commandment I give you. As I have loved you so you must love one another". "Bear one another's burdens and so fulfill the Law of Christ".