We know the duties that flow from the love of God and man by: (1) the Ten Commandments of God, (2) the Sermon on the Mount, especially in the Beatitudes, (3) the Spiritual and Corporal Works of Mercy, (4) the Theological and Cardinal Virtues, and (5) the laws of the Church.

1. We know the duties that flow from the love of God and man by the Ten Commandments of God.

The covenant between God and His people, which God delivered to Moses on Mt. Sinai, included, as an essential part of the message of Salvation, the Ten Commandments.

1. You shall have no other gods before Me.
2. You shall not take the Name of the Lord your God in vain.
3. Remember to keep holy the Lord’s Day.
4. Honor your father and your mother.
5. You shall not kill.
6. You shall not commit adultery.
7. You shall not steal.
8. You shall not lie.
9. You shall not covet your neighbor’s wife.
10. You shall not covet your neighbor’s goods.

Like the first People of God, we Christians are obedient to the commandments as our response to God’s love for us. By keeping His commandments, we surrender ourselves in obedience to God and unite ourselves to Him.

All of the commandments can be summarized in the two commandments of love of God and love of neighbor. Of the Ten Commandments, the first three show us how we must love God, and the last seven show us how to love others for the sake of God. The Ten Commandments are especially important because they teach us the specifics of morality. They contain the natural law which is made known to us by our human reason and which divine revelation confirms. The Old and New Testaments and the long use which the Church has made of the Ten Commandments testify to their importance in our lives.

2. We know the duties that flow from the love of God and man by the Sermon on the Mount, especially in the Beatitudes.

In the Sermon on the Mount, Jesus tells us how we can attain happiness in this life. The Beatitudes express the high standards of Christ’s Kingdom and the reward which is promised to those who live according to these standards. The primary reward promised in each of these Beatitudes is Heaven, but if we live according to the plan of Christ, we shall have a foretaste of the happiness of Heaven in this life.

The eight Beatitudes are: (1) Blessed are the poor in spirit, for theirs is the Kingdom of Heaven; (2) Blessed are those who mourn, for they shall be comforted; (3) Blessed are the meek, for they shall inherit the earth; (4) Blessed are those who hunger and thirst for righteousness, for they shall be satisfied; (5) Blessed are the merciful, for they shall obtain mercy; (6) Blessed are the pure in heart, for they shall see God; (7) Blessed are the peacemakers, for they shall be called sons of God; and (8) Blessed are those who are persecuted for righteousness’ sake, for theirs is the Kingdom of Heaven. Blessed are you when men revile you and persecute you and utter all kinds of evil against you falsely on my account. Rejoice and be glad, for your reward is great in Heaven, for so men persecuted the prophets who were before you. (cf. Mt 5:3-12 and Lk 6:20-23)

Our Lord tells us that we will be happy if we do, for His sake, the very things which many think will make them unhappy. He tells us that we should not set our hearts on money, that we must forgive our enemies and love them, that we must avoid all occasions of sin, and that we must be willing to suffer for His Name’s sake. Jesus has not only told us how to live; He has shown us by His example. Moreover, He gives us the help we need to follow His example.

3. We know the duties that flow from love of God and man by the Spiritual and Corporal Works of Mercy.

Some of the most important Works of Mercy are to: help convert the sinners, advise the doubtful, instruct the ignorant, comfort the sorrowful, bear wrongs patiently, pray for the living and the dead, feed the hungry, clothe the poor, support the homeless, visit the sick, and bury the dead.

4. We know the duties that flow from the love of God and man by the Theological and Cardinal Virtues.

Without God’s gift of charity to us, we would not be able to love God or one another as children of God. It is one of the great powers which He bestows on us along with the gift of sanctifying grace. God also gives us the powers to believe in Him and to hope in Him. These three powers are the virtues of faith, hope, and charity, called the “Theological Virtues” because they refer to God.

The cardinal or principal moral virtues are: prudence, which inclines us to form right judgments about what we should or should not do; justice, which inclines us to give to all men whatever is due to them; temperance, which inclines us to control our appetites according to what is right and pleasing to God; and fortitude, which inclines us to do what God desires, even when it is disagreeable or difficult.

5. We know the duties that flow from the love of God and man by the laws of the Church.

From time to time, the Church has listed certain specific duties of Catholics. The duties which are expected of Catholic Christians today are the laws of the Church. These laws, traditionally called the Precepts of the Church, concern the moral and Christian life, united with and nourished by the Sacred Liturgy. Some of them are: (1) to attend Mass every Sunday and holy day of obligation and to refrain from work and activities that could impede the sanctification of these days, (2) to receive the Sacrament of Penance and Reconciliation at least once a year, (3) to receive Holy Communion at least during the Easter Season, (4) to do penance, observing the prescribed days of fasting and abstinence, (5) to help provide for the needs of the Church.