In our last episode we saw that Christian morality is founded upon love. But it is a love that we cannot possibly fulfill in our own strength. In order to fulfill the duties of Christian morality, we must have God’s grace. So says Pope John Paul II in VS §22.
To imitate and live out the love of Christ is not possible for man by his own strength alone. He becomes capable of this love only by virtue of a gift received. As the Lord Jesus receives the love of his Father, so he in turn freely communicates that love to his disciples: “As the Father has loved me, so have I loved you; abide in my love” (Jn 15:9). Christ’s gift is his Spirit, whose first “fruit” (cf. Gal 5:22) is charity: “God’s love has been poured into our hearts through the Holy Spirit which has been given to us” (Rom 5:5). [Emphasis in original]
The Christian life—the Catholic life—is a life of grace. We are able to obey our Lord only as He enables us to do so. The Catholic cannot save himself. He cannot please God in his own strength. He must have grace.