There are two opposing views of grace and they stand in direct opposition. They are not complimentary, they are competitive. One cannot prosper without destroying the other.
In the one view, grace is a mechanism by which Christ made it so that the atonement serves as a proxy for righteous behavior. That is different than forgiveness on condition of repentance. In this view grace serves as a proxy substituting even for our current flaws and failings. This interpretation was initiated by Martin Luther. It tends to be taught using phrases like "Christ already paid the bill in full" and is the underlying view of the atonement in protestantism. It is through this lens that Paul's words are read in protestant religions.
But viewed correctly, grace is simply the merciful gifts of God. Some of them came by the atonement, others, such as the creation, and the gift of a moral body, came independent of it. While it is true that many of God's gifts are given on condition of obedience, that doesn't mean that it is our works that bring it to us. That is outside our mortal power. I can live so the Holy Ghost will choose to attend me, but that is different that saying that by my own mortal abilities I have forced the Holy Ghost to attend me. The Holy Ghost is a god. He will do as he sees fit. And if he attends me when I am righteous, that is a merciful gift, not something I did by my own mortal power. It is simply a merciful gift, gifted to me on condition of obedience. This grace comes into our life in recognizable ways that are fundamental parts of our doctrine. The light of Christ is a manifestation of the grace of God. If we follow if, then it leads to the grace of baptism for remission of sins, and to the grace of the gift of the Holy Ghost. These examples of grace can transform our works. They cannot transform the fact that our power is meerly that of mortal men. But they can transform our works, which is essential to us, because it is by our works that we will be judged. The resurrection, and sealing to an eternal spouse are other examples of this grace. It is outside our power as mortals to bring ourselves forgiveness, the light of Christ, the Holy Ghost, resurrection from the dead, eternal sealing, or exaltation. That does not mean they are not conditioned on obedience, it means they are outside our ability to grant to ourselves. We are saved by grace, after all we can do.
In short, contrasting the two, in the protestant view of grace Christ's atonement not only provides forgiveness on condition of repentance, but also provides proxy righteousness substituting even for our current failings and flaws.