I was asked by a Rabbi what the Hebrew word for the Christian concept of "grace" might be (I read Biblical Hebrew). Here was my immediate response:
Strong's Hebrew Lectionary of the New American Standard Version of the bible says in Hebrew grace is h8467. תחנה techinnah; from 2603a; favor, supplication for favor:-- grace (1), mercy (1), petition (4), supplication (18), supplications (1). Or h2580. חנ chen; from 2603a; favor, grace:-- adornment (1), charm (1), charm *(1), charming *(1), favor (51), grace (8), graceful (2), gracious (3), pleases *(1).
I think grace in Hebrew would be less like "blessing" h0835. אשׁר esher;, and more like "to be made/able to stand" h6965. קומ qum; or h5975. עמד amad;
Grace and the Law are inexorably linked. In Christian teaching, Torah can not be filled by us in our natural state, the supernatural importation of grace allows for its fulfillment. Grace is giving you more than you deserve (the grace period on a bill perhaps). Mercy is withholding what you do deserve (when David didn't kill Saul that time they were in the cave).
Have attached a couple pages on grace and the law that might be elucidating. The highlight of that text is: "(e) Thus the revelation of grace, while it takes up and includes in itself the revelation of law,-a.dds something different in kind; namely the mani-festation of the personal love of the Lawgiver. Without grace law has only a demanding aspect. Only in connection, with grace does it become "the perfect law, the law of liberty" (James 1 25). In fine, grace is that larger and completer manifestation of the divine nature, of which law constitutes the necessary but preparatory stage." Systematic Theology: A Compendium -Augustus Strong