David A. Bednar (October 2007 Conference)

But remission of sin is not the only or even the ultimate purpose of the gospel. To have our hearts changed by the Holy Spirit such that "we have no more disposition to do evil, but to do good continually" (Mosiah 5:2)... is the covenant responsibility we have accepted. This mighty change is not simply the result of working harder or developing greater individual discipline. Rather, it is the consequence of a fundamental change in our desires, our motives, and our natures made possible through the Atonement of Christ the Lord. Our spiritual purpose is to overcome both sin and the desire to sin, both the taint and the tyranny of sin.

Helaman 3:35

35. Nevertheless they did fast and pray oft, and did wax stronger and stronger in their humility, and firmer and firmer in the faith of Christ, unto the filling their souls with joy and consolation, yea, even to the purifying and sanctification of their hearts, which sanctification cometh because of their yielding their hearts unto God.