Sometimes he would reference the OT law to explain what the spirit of the law was. Like in the Sermon on the Mount. That was even harder to hear--it was tough enough to try to keep all of the law perfectly in practice and then Jesus would take it to the intended level--the spirit of the law. The point in all of his teaching was to set up his main message: God has some really good news. Because of his great love, God would extend grace toward his human creation. He was providing a way for them to have an eternal love relationship with him and each other.