Doesn't grace replace the Law?

No, and this is one of the biggest misunderstandings in modern Christianity. We are taught that the Law was the old, harsh system and grace is the new, kind one that replaced it. But that opposition is not actually in the Hebrew Bible. It was built much later by Western theologians.

Think of it this way. Grace, in Hebrew chesed, is God's faithful, committed love, the kind that keeps a relationship going even when we fail. The Torah is His instruction for how to live well inside that relationship. One is the love that holds a marriage together; the other is how you actually live as a married person. They were never rivals. They were always partners.

Grace does not cancel God's instructions. It gives you the heart to want to keep them. Even Sha'ul (Paul), the apostle most often quoted to argue the Law is gone, was a Torah-keeping Jew who loved it his whole life.