I first learned about the Enabling Power of the Atonement in a devotional address given by then BYU-Idaho President David A. Bednar.  Elder Bednar repeated some of the principles he discussed in the devotional after he became a member of the Quorum of the Twelve.

Some excerpts:

The framework for my message today is a statement by President David O. McKay. He summarized the overarching purpose of the gospel of the Savior in these terms:

. . . the purpose of the gospel is . . . to make bad men good and good men better, and to change human nature (from the film Every Member a Missionary, as acknowledged by Franklin D. Richards, CR, October 1965, pp. 136-137; see also Brigham Young, JD 8:130 [22 July 1860]).

Thus, the journey of a lifetime is to progress from bad to good to better and to experience the mighty change of heart–and to have our fallen natures changed.

May I suggest that the Book of Mormon is our handbook of instructions as we travel the pathway from bad to good to better and to have our hearts changed. Please turn with me to Mosiah 3:19. In this verse King Benjamin teaches about the journey of mortality and about the role of the atonement in successfully navigating that journey.

For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord . . . (emphasis added).

Now I want to stop at this point and draw our attention to two specific phrases. First, consider “and putteth off the natural man.” Let me suggest to you that President McKay was fundamentally talking about putting off the natural man when he said, “The purpose of the gospel is to make bad men good.” Now I do not believe the word “bad” in this statement by President McKay connotes only wicked, awful, horrible, or inherently evil. Rather, I think he was suggesting that the journey from bad to good is the process of putting off the natural man or the natural woman in each of us. In mortality we all are tempted by the flesh. The very elements out of which our bodies were created are by nature fallen and ever subject to the pull of sin, corruption, and death. And we can increase our capacity to overcome the desires of the flesh and temptations, as described in this verse, “through the atonement of Christ.” When we make mistakes, as we transgress and sin, we are able to overcome such weakness through the redeeming and cleansing power of the atonement of Jesus Christ.

. . . .

Now, please notice the next line in Mosiah 3:19: “and becometh a saint.” May I suggest this phrase describes the continuation and second phase of life’s journey as outlined by President McKay. “The purpose of the gospel is to make bad men good”–or, in other words, put off the natural man–”and good men better”–or, in other words, become more like a saint. Now, brothers and sisters, I believe this second part of the journey, this process of going from good to better, is a topic about which we do not study or teach frequently enough nor understand adequately.

If I were to emphasize one overarching point this afternoon, it would be this. I suspect that you and I are much more familiar with the nature of the redeeming power of the atonement than we are with the enabling power of the atonement. It is one thing to know that Jesus Christ came to earth to die for us. That is fundamental and foundational to the doctrine of Christ. But we also need to appreciate that the Lord desires, through His atonement and by the power of the Holy Ghost, to live in us–not only to direct us but also to empower us. I think most of us know that when we do things wrong, when we need help to overcome the effects of sin in our lives, the Savior has paid the price and made it possible for us to be made clean through His redeeming power. Most of us clearly understand that the atonement is for sinners. I am not so sure, however, that we know and understand that the atonement is also for saints–for good men and women who are obedient and worthy and conscientious and who are striving to become better and serve more faithfully. I frankly do not think many of us “get it” concerning this enabling and strengthening aspect of the atonement, and I wonder if we mistakenly believe we must make the journey from good to better and become a saint all by ourselves, through sheer grit, willpower, and discipline, and with our obviously limited capacities.

Brothers and sisters, the gospel of the Savior is not simply about avoiding bad in our lives; it is also essentially about doing and becoming good. And the atonement provides help for us to overcome and avoid bad and to do and become good. There is help from the Savior for the entire journey of life–from bad to good to better and to change our very nature. Indeed, this doctrine tastes good.

I am not trying to suggest that the redeeming and enabling powers of the atonement are separate and discrete. Rather, these two dimensions of the atonement are connected and complementary; they both need to be operational during all phases of the journey of life. And it is eternally important for all of us to recognize that both of these essential elements of the journey of life–both putting off the natural man and becoming a saint, both overcoming bad and becoming good–are accomplished through the power of the atonement. Individual willpower, personal determination and motivation, and effective planning and goal setting are necessary but ultimately insufficient to triumphantly complete this mortal journey. Truly, we must come to rely upon “the merits, and mercy, and grace of the Holy Messiah” (2 Nephi 2:8).

You can find the entire devotional at http://www.byui.edu/Presentations/Transcripts/Devotionals/2002_01_08_Bednar.htm and I highly recommend it.