We read in Matthew 5:17-19 KJV
[17] “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. [18] For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled. [19] Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them , the same shall be called great in the kingdom of heaven.”
Jesus isn’t changing the law. So what’s happening in Matthew 19?
Matthew 19:3-9 KJV
[3] “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? [4] And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female, [5] 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? [6] Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder. [7] They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away? [8] 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. [9] 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.”
The G-d of the Old Testament and the G-d of the New Testament are one and the same. Jesus said he wasn’t changing the law. G-d doesn’t misspeak. So how are these in harmony? I think the key is where Jesus didn’t say the Law he said “Moses”. That is important. Moses apparently gave them latitude with the Law of G-d that wasn’t what G-d was permitting. Look at Deuteronomy 24.
Deuteronomy 24:1 KJV
[1] “When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes, because he hath found some uncleanness in her: then let him write her a bill of divorcement, and give it in her hand, and send her out of his house.”
It would seem that the “uncleanness” spoken of by G-d in Deuteronomy is sexual immorality. In the New Testament Jesus clarifies it. He doesn’t change the Law.
Adultery carried the death penalty under the law so no divorce necessary, right? But wait, there had to be witnesses for that to happen. This statute is to provide a husband with a remedy in the case that he found out his wife had committed adultery but he couldn’t prove it in a court of law, so to speak.