Our salvation begins with God's initiation and grace. Similarly, our sanctification too will be a product of God's grace by the work of the Holy Spirit. Indeed, we are not perfected in knowing, but we are perfected in love. We will not overcome sin by hating sin but by loving Jesus.
All the divine precepts are, therefore, referred back to love, of which the apostle says, "Now the end of the commandment is love, out of a pure heart, and a good conscience and a faith unfeigned." Thus every commandment harks back to love. For whatever one does either in fear of punishment or from some carnal impulse, so that it does not measure up to the standard of love which the Holy Spirit sheds abroad in our hearts--whatever it is, it is not yet done as it should be, although it may seem to be. Love, in this context, of course includes both the love of God and the love of our neighbor and, indeed, "on these two commandments hang all the Law and the Prophets" --and, we may add, the gospel and the apostles, for from nowhere else comes the voice, "The end of the commandment is love," and, "God is love."
- St. Augustine, Enchirdion on Faith, Hope and Love, trans Albert C. Outler (1955), XXXII.