There is a new law that came with Jesus Christ, but it is not always understood that it is only one commandment. Beyond that, there is only the fulfillment of the laws of the Old Testament. The commandments of the Old Testament still apply to us. Jesus only explained them for us. Regarding the commandment against adultery, Jesus explained it for us: “Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.” Matthew 5:27-28. Some people think Jesus was just making the law stricter, telling Christians they have to go beyond resisting adultery to not even thinking about it. Therefore, God would be the judge of thoughts. The truth is that God was always the judge of thoughts and rebellious thoughts were always regarded as sin. “Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women. Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also? And the Lord said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old? Is any thing too hard for the Lord? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son. Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.” Genesis 18:11-15. God read her mind and knew her unbelief. He required obedience even in the minds of his servants. Jesus was not making the law stricter. He was explaining the law. We have to keep even our thoughts sinless. We all fail at that, just like Sarah.
There are three levels of sin: the thoughts, the words, and the actions. If we can stop sin at the thought level, it will not go to the speech level. If it gets to the speech level, stop it before it changes to sinful actions. Sinful actions can result in disaster in our relationships with God and people. “For though we walk in the flesh, we do not war after the flesh: (For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;) Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;” 2 Corinthians 10:3-5. The battle is for our minds. When we dwell on evil thoughts, we must repent of them and ask God for forgiveness. Sometimes evil spirits will try to inject evil thoughts into our minds. We must tell those creatures to leave in the name of Jesus, and confess our sin of dwelling on those thoughts if we did not immediately reject them. We constantly sin in our thoughts, but the sacrifice of Jesus Christ is sufficient to cleanse us of all sin, and his mercy is boundless.
Therefore, Jesus did not add to the law. He explained it. The people did not understand the law. He explained the requirements of the commandments, but it is necessary to have the laws written on our hearts, which happens when we accept Christ and receive the anointing of the Holy Spirit. Then we have the power to keep the laws and resist evil. With that relationship we enter an exalted state of priesthood, higher than the Levitical priesthood, for we are under our high priest, Jesus Christ of the order of Melchisedec. It is then our duty to intercede for our nation, whatever Israel nation we are part of. Therefore, the Old Testament law is fulfilled in Christ Jesus. He did not destroy it, but allowed us to enter into a higher form of obedience and sanctification by his death and resurrection. His death satisfied the law of sacrifice. No further sacrifice is required. He only gave us one new law: “A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another. By this shall all men know that ye are my disciples, if ye have love one to another.” John 13:34-35.
There is nothing the Lord would not do for his disciples. He even gave up his mortal life for them.