Catholic morality teaches us a way of life that is worthy of human beings who are adopted sons and daughters of God. We must grow in the new life which God gave us through Jesus Christ.
The Catholic Church expresses the fullness of Christian moral teaching by stating moral precepts or commands, by making judgments about the morality of certain actions, and by making laws that concern the implementation of moral principles and precepts. The Church’s teaching expresses the will of God that we become both sharers in Christ’s risen life and children in His holy family. We are to live lives worthy of the members of a community of worshippers and believers who are destined for Heaven.
The moral laws which govern human conduct come from an unchanging God and apply to an unchanging human nature. Whatever might be said in favor of the theory of human evolution, once rational man, i.e., homo sapiens, appeared on the earth, his nature has not changed one iota. The first rational human beings were essentially the same as those who live today. Therefore, the natural laws that must govern man’s moral conduct remain the same. Thus, it will always be sinful to lie, to cheat, to gossip, to commit adultery, to contracept, to abuse others, to torture, etc.