The longer I read from those men and women who have gone before us, and who "have already been through the test with flying colors," as Clement puts it, the more I see that they're all all telling the same story. What I like so much about C.S. Lewis is how he speaks to our dignity as sons and daughters of God, as he so eloquently does in The Weight of Glory. This opening passage of Thomas Merton in Life and Holiness resonates deeply with me on the same theme.
Every baptized Christian is obliged by his baptismal promises to renounce sin and to give himself completely, without compromise, to Christ, in order that he may fulfill his vocation, save his soul, enter into the mystery of God, and there find himself perfectly "in the light of Christ."
As St. Paul reminds us (1 Cor. 6: 19), we are "not our own." We belong entirely to Christ. His Spirit has taken possession of us at baptism. We are the Temples of the Holy Spirit. Our thoughts, our actions, our desires, are by rights more his than our own. But we have to struggle to ensure that God always receives from us what we owe him by right. If we do not labor to overcome our natural weakness, our disordered and selfish passions, what belongs to God in us will be withdrawn from the sanctifying power of his love and will be corrupted by selfishness, blinded by irrational desire, hardened by pride, and will eventually plunge into the abyss of moral nonentity which is called sin.
Sin is the refusal of spiritual life, the rejection of the inner order and peace that come from our union with the divine will. In a word, sin is the refusal of God's will and of his love. It is not only a refusal to "do" this or that thing willed by God, or a determination to do what he forbids. It is more radically a refusal to be what we are, a rejection of our mysterious, contingent, spiritual reality hidden in the very mystery of God. Sin is our refusal to be what we were created to be-sons of God, images of God. Ultimately sin, while seeming to be an assertion of freedom, is a flight from the freedom and the responsibility of divine sonship.
Every Christian is therefore called to sanctity and union with Christ, by keeping the commandments of God.