The apostle Paul wrote, “Now we know that what things soever the law saith, it saith to them who are under the law: that every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.” Romans 3:19-20. Paul went on to say that we are justified by faith in Jesus Christ, which is what the Reformation preachers believed. However, the law is still important because it defines what sin is, and what it is not. First, we must define what the Bible means by “the law”.
The traditional definition of the law is that it is the first five books of the Bible, being the books of Moses. However, Jesus expanded on that definition. “Jesus answered them, Is it not written in your law, I said, Ye are gods? If he called them gods, unto whom the word of God came, and the scripture cannot be broken; Say ye of him, whom the Father hath sanctified, and sent into the world, Thou blasphemest; because I said, I am the Son of God?” John 10:34-36. He was referring to Psalm 82:6. He was including that portion of the Psalms as part of the law. I believe he was expanding the definition of the law to include the works of the prophets, because the Psalms are actually works of the prophets; they were written by prophets.
The apostle Paul wrote, “In the law it is written, With men of other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord.” I Corinthians 14:21. He was referring to Isaiah 28:11-12. Therefore, the apostle was including the works of the prophet Isaiah as part of the law. The law is bigger than just the first five books of Moses. Moses led the way, but there were many prophets after him. I believe the works of all of those prophets instruct us in the law and give us knowledge of what is sin and what is not sin.
Did prophecy end with the Old Testament? John the Baptist, the Lord, and the apostles all prophesied. I believe that by extension we should include the New Testament as part of the law. Jesus said there is a new standard of obedience for his followers that goes beyond the Law of Moses. “The Pharisees also came unto him, tempting him, and saying unto him, Is it lawful for a man to put away his wife for every cause? And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh? Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder.
They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away? He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so. And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.” Matthew 19:3-9. Christian marriages go beyond the Law of Moses. They are life-long and are based on commitment to each other through changed hearts by the Holy Spirit.
The Law of Moses allowed for slavery. “Both thy bondmen, and thy bondmaids, which thou shalt have, shall be of the heathen that are round about you; of them shall ye buy bondmen and bondmaids. Moreover of the children of the strangers that do sojourn among you, of them shall ye buy, and of their families that are with you, which they begat in your land: and they shall be your possession.” Leviticus 25:44-45. However, the New Testament says that all Christians are free. “If the Son therefore shall make you free, ye shall be free indeed.” John 8:36. Christianity liberates people from slavery. We see that the Law of Moses by itself is not sufficient to guide us into righteousness. The whole Bible must be considered – every part of it.