The “Law” required what it could not give.
“Grace” gives that which it requires.
Author unknown
The law orders; grace supplies the power of acting.
Augustine of Hippo
If the Spirit of grace is absent, the law is present only to convict and kill.
Augustine of Hippo
That thy walk with God in the way of obedience is not to fulfil the law, as a covenant of works. Thou art not required to do this. Thou canst not do it. Immanuel, thy divine surety, took it upon Himself. Because it was impossible for thee, a fallen creature, to keep the law, so as to be justified by it, He therefore came in person to fulfil it. He honored its precepts by His infinite obedience. He magnified its penalties by His inestimable sacrifice. And this is thy justifying righteousness. Through faith in the life and death of the God-man thou art not only freed from guilt and condemnation, from curse and hell, but art also entitled to life and glory. The law is now on thy side, and is become thy friend. It acquits thee. It justifies thee. It will give thee the reward promised to obedience. The law in the hand of thy Savior has nothing but blessings to bestow upon thee. Thou art to receive it at His mouth and to obey Him: but not from any legal hopes of heaven, or from any slavish fears of hell: for then thou wouldst come under the covenant of works again. Whereas thou art not under the law, but under grace, mind thy privilege and pray for grace to live up to it. Thou art not under the law, bound to keep it perfectly in thine own person, or in case of failing, condemned by it, and under its fearful curse. Thou art under grace, a state of grace through faith in the obedience and sufferings of thy blessed surety, and under the power of grace constrained and motivated by the love of Christ.
William Romaine