The time honored definition of grace has always been "unmerited favor" given by God to men. Such a definition lends itself to the narcissistic 'other gospel' which revolves around the importance of man in his own eyes and brings no glory to the One issuing His grace. The "unmerited favor" view of grace centers around the unworthiness of man and usually ends up in a self-pity party that also brings no glory to God. No one is "worthy" of any of the goodness of God, not life in the soul or breathe in the nostrils---nothing. So get over it! Get past your own worthlessness and focus on the One who is Worthy; the same One who has made us worthy in the sight of His Father by His sacrifice. Further, to say that grace is 'unmerited' could too easily be seen as something that we received because we requested God's 'favor,' especially when it comes to the saving of our soul. Such a notion cannot be supported by specific Scripture, nor by general theme found therein. If the granting of His saving grace is based upon our 'unmerited' status where does His sovereign choice enter the equation? What man is there that could legitimately claim to merit His grace, and if he did merit it, he wouldn't need it. Following this illogic will lead to universalism in about two more steps.
Left intact and unchallenged, this current definition of grace has been used successfully by the wicked one to keep people ignorant of the work of Christ in the heart of the believer. It puts the focus on man, how lucky he is to have received this 'unmerited favor' when the fact is that 'luck' had nothing to do with it (it was the sovereign choice of God). It cheapens grace by making the recipient---man---the stealthy focus instead of Christ. We were saved "by grace" in order that our newly created life (2 Cor. 5:17) would be to the eternal glory of the Savior, with absolutely no regard for our old man, it's nature, or it's unworthy, unmeritable status. Our old man died with Christ, Rom. 6:6 & 7 and Gal. 2:20; our new man is raised in His likeness (Rom. 6:4 & 5). The receipt of grace by any man is due solely to the discretion and choice of the Father. The focus of grace, it's issuance and it's results, are always and forever to glorify the Lord Jesus. The continued giving of grace to the believer cannot be characterized as "unmerited" because the believer, whether a new babe or long time saint has been made worthy in all respects due to the sacrifice of the Lord Jesus. To say that a believer in Christ is unworthy would refer, in typical narcissistic & other gospel fashion, to the dead fallen nature that God now sees as non-existent, dead, and powerless (Rom. 6:14).
There are a few verses that totally destroy this notion of "unmerited favor" being the correct definition of grace. John 1:14; "And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of [unmerited favor] grace and truth." How ridiculous and blasphemous it sounds to plug in the popular notion of grace. To do so would mean that Christ is full of unmerited favor and therefore lacking in merit, the fantasy of all religions made by man. Then there is Luke 2:40; "And the Child grew and became strong in spirit, filled with wisdom and the [unmerited favor] grace of God was upon Him. If "unmerited favor" is a valid and legitimate definition of grace why do not it's proponents take the next step and declare Christ to be unworthy? Most already have, but not in the same breath. Heb. 2:9 says; "But we see Jesus, who was made a little lower than the angels, for the suffering of death crowned with glory and honor, that He, by the [unmerited favor] grace of God might taste death for everyone." In order for this "unmerited favor" nonsense to be maintained, one must conclude from this preceding verse alone that the Lord Jesus Christ was unacceptable to the Father in His Sonship alone and that the favor granted Him was because, in His "unworthy" state, it was necessary to infuse this 'unmerited favor' in order to validate His sacrifice. Many are the heretics of our day that teach that Christ's sacrifice was unnecessary or insufficient. To accommodate the 'unmerited favor' definition of grace plays right into their hands and is an affront to the Savior.
Perhaps a better starting point to more fully understand and appreciate the Grace of God would begin by referring to it as "enabling power." Even this is just a beginning and is by no means meant as an exclusive or all-encompassing definition. The Grace of God is also an eternal study. It is hindered by hanging on to junk theology that leads in the wrong direction. May it please the Lord to grant grace to the hearer to love His Word and search it diligently.