Don’t misunderstand why I have come. I have not come to abolish the law of Moses or the writings of the prophets. No, I came to accomplish their purpose. Matthew 5:17 NLT
True circumcision is not merely obeying the letter of the law; rather it is a change of heart produced by the Spirit. Romans 2:29 NLT
In his so-called “Sermon on the Mount” as reported in Matthew chapter 5-7, Jesus took what was then a radical approach to the Jewish Law, the Torah. Up until that point, it was understood that the Law was centrifugal, that is, it was a closed circle with all the influences pointing inward. That is, the instructions in the law were all self-contained and limiting. Here is what you could and could not do and if you stayed within those limitations you had fulfilled all your obligations.
So, your sexual obligation was to be faithful to your spouse. Beyond that, your sexual life was your own. Similarly, if you did not actually murder a person, how you treated persons was pretty much up to you. And so forth. Stay inside the circle of those limitations and you were ok.
But Jesus came along and completely blew up that idea. The Torah was intended to be centripetal. Its influences were all intended to be directed outward. Paul understood this very well, expressing it with the language of “the spirit of the law” versus “the letter of the law” (cf. 2 Cor 3:6). The Torah, expressing the idea in very concrete terms, was intended to point beyond itself to a transformation.
The law about adultery was intended to point outward: it was not merely about not being unfaithful to your spouse, but about whether you used another – in any way – to gratify your sexual desires. The command not to murder was likewise intended to point outward. The idea of protecting someone’s physical life was intended to issue in behavior that would protect a person’s value and worth. The question about divorce was not about whether it was permitted, but about what you did to your spouse in the process.
Instead of the Torah’s function being to establish limits, its function was to establish directions. So Jesus could say, “I have not come to erase the Torah. No, I came to show you what it is really about.