Paul conceives the Mosaic (old) covenant as fundamentally non-eschatological in contrast to the eschatological nature of the new covenant. Paul declares that the Mosaic covenant is not old because it belongs to the old age, whereas the new covenant is new because it belongs to the new eschatological age. This distinction has determinative effects. The old age is transitory and impotent, and therefore the Mosaic covenant is both transitory and ineffectual. The new covenant is both eternal and effectual because it belongs to the new age and partakes of the power of the new age, the Holy Spirit.
Another way to state the difference is as follows. As the eschatological covenant, the new covenant consists of what one would call "eschatological intervention," while the old covenant does not. God intervenes through His Spirit in the new eschatological age in order to create what He calls the new covenant. The Mosaic covenant lacked the power to produce what it demanded. (p.1-2)
(4) We should never under estimate the lack of actual power that the Law in itself has. The Law, according to Paul, in the end stirs up sin. This is because of the human who enters into the covenant with God through the Law not God, or the Law which is holy, righteous and good. Hebrews, too, identifies the same problem with the Law.
Hebrews 8:7 For if that first covenant had been faultless, there would have been no occasion to look for a second.