Why does old Adam give up trying to keep the law?
Old Adam gives up trying to keep the law because he knows he cannot keep it anyway. Even though he may recognize that stealing and similar things are wrong, the flesh has no ability to obey. The new nature, guided by the Holy Spirit, does not share that problem.
Les explains that old Adam can recognize moral wrongs—he knows it is wrong to steal and to do those things—and may even know he should try to keep the law. But old Adam also knows he cannot keep it anyway, so pretty soon he gives up. The new nature does not have that problem. Under the Holy Spirit’s guidance, believers realize they cannot keep the law by the energy of the flesh; it is impossible. When the Holy Spirit leads, guides, and directs, the law takes care of itself. Believers are delivered from the law, that being dead wherein they were held, so they should serve in newness of Spirit and not in the oldness of the letter—a whole new ball game.
But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.