The gospel calls for repentance, and one’s repentance is not sincere unless one undertakes to lead a sinless life. But even though the gospel promises a wealth of true human goods as a motive to repent, it cannot promise what sin offers here and now. Thus, people can deliberately prefer darkness to light; unwillingness to give up sin is their basis for unbelief.57 It is unanswerable, not because it is an argument which cannot be answered, but because it is a nonrational commitment which is impervious to argument.
Christian faith includes more than assent to true propositions; it is a commitment to follow Jesus. In this fallen world, however, those who consistently follow Jesus do not have easy lives. They must share in his cross as they cooperate in his uncompromising struggle against evil. Hence, typically, they have fewer material goods, fewer enjoyments in life, and less freedom to do as they please than if they compromised with evil. Accepting and holding fast to the cross is especially hard for the wealthy, self-indulgent, and powerful, whose faith is choked by the riches, pleasures, and cares of life (see Mt 13.22, Mk 4.19, Lk 8.14).
To follow Jesus means escaping from enslavement to disordered desires for riches, enjoyment, and status, and undertaking to live in obedience to God and in right relationships with and among men and women—the new covenant’s communion with God and neighbor. This communion is Christian love, which takes shape in specifically Christian modes of response (see CMP, 26). Only gradually, however, do these becomes second nature, for they are not “natural” to fallen humankind. Thus, the fallen human condition resists faith’s challenge. Many people are like the rich young man of the gospel (see Mt 19.16–22; cf. Mk 10.17–22, Lk 18.18–25): they experience a certain sadness and lethargy at the prospect of seriously undertaking to live the Christian life.
In every deliberate sin, freedom of self-determination is exercised contrary to what is known to be truly right and good. In sinning, sinners tend to regard moral truths legalistically, as if they were mere rules blocking them from doing as they please. Thus, deliberate sin seems to be self-affirming. Affirming the self and rejecting the limits which deny some forbidden fruit, sinners try to be autonomous, as only God really can be.58
Faith demands renunciation of this sinful self: pride must give way to humility. Humility is not self-depreciation, but readiness to accept everything good as God’s gift and to thank him for it (see S.t., 2–2, q. 161, aa. 2–3; CMP, 26.D). It is not self-negation, but escape from isolated and sterile autonomy into authentic self-fulfillment, to be realized and enjoyed in the only way possible: by sharing, as a member of God’s family, both in his blessedness and in every human good. From the viewpoint of pride, however, humility seems to threaten the self. Thus, sinners who lack faith, as well as believers whose faith has been weakened by a habit of sinning, will be tempted to reject faith in order to avoid self-renunciation, that is, renunciation of their sinful selves (see Jn 3.16–21).
57. See John XXIII, Ad Petri Cathedram, AAS 51 (1959) 502, PE, 263.20: “Once we have attained the truth in its fullness, integrity, and purity, unity should pervade our minds, hearts, and actions. For there is only one cause of discord, disagreement, and dissension: ignorance of the truth, or what is worse, rejection of the truth once it has been sought and found. It may be that the truth is rejected because of the practical advantages which are expected to result from false views; it may be that it is rejected as a result of that perverted blindness which seeks easy and indulgent excuses for vice and immoral behavior.”
58. See Congregation for the Doctrine of the Faith, Instruction on Christian Freedom and Liberation, 37, AAS 79 (1987) 568–69, OR, 14 Apr. 1986, 3.