A new look at the moral life has been informed by the biblical renewal in the Church and by some philosophical shifts within the Church and society.

For example, the biblical renewal has given us covenant, heart and conversion—not law—as our primary moral concepts. Responsibility has replaced obligation as the primary characteristic of the moral life. Shifts in philosophy have emphasized the dignity of persons and the value of sharing life in society. Together these shifts in theology and philosophy support a relational model of the moral life. The relational model emphasizes personal responsibility for protecting the bonds of peace and justice that sustain human relationships.

 Sin is just as basic a term in our Christian vocabulary today as it has been in the past. Its root sense means to be disconnected from God through the failure to love. In sin, we simply don't bother about anyone outside ourselves. Sin is first a matter of a selfish heart—a refusal to care—before it shows itself in actions. Because loving God and loving our neighbor are all tied together, sin will always be expressed in and through our relationships.

The Catechism of the Catholic Church affirms that, just as the least of our acts done in charity has some benefit for all, so every sin causes some harm. The Catechism quotes Scripture to make this point: "None of us lives for oneself, and none of us dies for oneself" (Rom 14:7); "If one member suffers, all suffer together; if one member is honored, all rejoice together. Now you are the body of Christ and individually members of it" (1 Cor 12:26-27); "Charity does not insist on its own way" (1 Cor 13:5; see 10:24). In this solidarity with all people, says the Catechism, "living or dead, which is founded on the communion of saints, the least of our acts done in charity redounds to the profit of all. Every sin harms this communion" (#953).

One of the most obvious changes in a contemporary approach to sin is the emphasis given to how sin affects the quality of life and love in our relationships. Sin is any action or omission that hinders, violates or breaks right relationships which support human well-being. For example, if I spread gossip or fail to correct a false rumor about a co-worker, I am not only failing in my relationship to that person, but also impairing the quality of life in the workplace.

Right moral living begins with caring for one another: paying attention to another's needs and acting in a way that enhances another's well-being. Sin, by contrast, turns in and sets oneself against another. Self-serving interests destroy the bonds of peace and justice that ought to sustain us.