Jared C. Wilson in his book, Your Jesus is Too Safe, makes this statement. "We don't follow the Law to get saved, we follow the Law because we are saved."
So, the answer to the question, "Do I need to hear the Law?" is an absolute "Yes!" But, that answer must be qualified because the law is not a means, it is an end. It is what we do because we are saved. It makes no sense to preach the Law in any shape or form without the cause, which is our salvation as found in Jesus Christ. Paul did not say "I preach the Law" (although his writings are full of examples of what our new behavior should look like), but he said that "we preach Christ crucified: a stumbling block to Jews and foolishness to Gentiles." (1 Cor 1:23) Look at any example of Paul's preaching of any type of behavior, and then look at what precedes it, a Gospel message, a proclamation of Christ. The two are never apart.
Head on over to the Sermon on the Mount for a minute. In it, Jesus tells us plenty of things to do. Or does He? Is He giving us a list of "to do's," or is He telling us what we should be? Is He introducing a new form of legalism or is He trying to reshape the way people think of religion? I believe it is the latter.
In one of Tim Keller's sermons, he talks about the conclusion to the Sermon on the Mount, the Wise and Foolish builders, and how we normally interpret them. We see the foolish builder as one who does not obey Christ in any sense, a rebel who rejects Him. But does that conclusion make sense in light of a sermon where Jesus has just contrasted two types of people who say they believe? One who follows the law (as in Mt. 5:27-29) and says "I have never commited adultery!" and the other who lives by Jesus's challenge, that "everyone who looks at a woman with lustful intent has already committed adultery with her in his heart." Or Matthew 5:43-44, where he tells us to love our enemies, because God sends His rain on the just and the unjust, in spite of the fact that they have heard that they should love their neighbors and hate their enemies. There are many other examples of this contrasting found in Matthew chapters 5-7 as well, too many to list. So what he concludes with is two houses, both look the same on the outside. Both follow the Law, but only one house will stand. And that is the house on the rock. Not the one that looks good but is attached to the sand of self and accomplishments. Not that one for it relies on the sand works to save it. No, it is the house on the rock that stands. The one whose foundation reaches deep into the teachings and knowledge of God. The one who, out of a deep understanding of the Gospel and therefore a deep love for Christ, not only follows the letter of the law, but the spirit of it as well.
Who needs the Law? I do, for it reveals my sinfulness and need for Christ.