Do not think that I came to abolish the Law or Prophets. I came to fulfill them.
“Do not think that I have come to abolish the law or the prophets. I have come not to abolish but to fulfill. Truly, I say to you, until heaven and earth pass away, not the smallest letter or the smallest part of a letter will pass from the law, until all things have taken place. Therefore, whoever breaks one of the least of these commandments and teaches others to do so will be called least in the kingdom of heaven. But whoever obeys and teaches these commandments will be called greatest in the kingdom of heaven. I tell you, unless your righteousness surpasses that of the scribes and Pharisees, you will not enter into the kingdom of heaven. Matthew 5:17-20
God’s revelation of Himself and His will in the Old Testament was not abrogated by Jesus. Instead it was amplified, and clarified, and made possible by Jesus. Just knowing about these things is not enough. They must consume us. We can now have intimacy with God and know Him from within and hear Him constantly through His Spirit. We can not just know about His ways but actually live in them through the power of His Spirit.