Jesus said in the Sermon on the Mount: "Blessed are the poor in spirit, for theirs is the kingdom of heaven. Blessed are they who mourn, for they will be comforted. Blessed are the meek, for they will inherit the land. Blessed are they who hunger and thirst for righteousness, for they will be satisfied. Blessed are the merciful, for they will be shown mercy. Blessed are the clean of heart, for they will see God. Blessed are the peacemakers, for they will be called children of God. Blessed are they who are persecuted for the sake of righteousness, for theirs is the kingdom of heaven" (Matt. 5:3-10). These are the "beatitudes", a word which means "perfect happiness". They are called the beatitudes because true happiness should be the result of practicing these beatitudes (CCC 1718).
The "poor in spirit" are those who love the humble condition of the poor, and practice this humility. Those who "mourn" are those who experience sadness, especially when doing God's will in difficult situations, with hope and trust in God. The "meek" are the "lowly" who are looked down upon by others because they do the will of God. Those "who hunger and thirst for holiness (or righteousness)" are those who pursue God and His grace, and what is according to His will, rather than the things of the world. The "merciful" are those who have mercy on others that have offended them. The "pure in heart" are those whose hearts are cleansed of any sinful desire or inclination, and have a "heart" for God and the goodness He desires His people to have. The "peacemakers" are those who promote harmony and good will among others, and do what they can to prevent or resolve conflict. Those who are "persecuted for the sake of righteousness" are those who patiently endure the backlash they receive for doing right.
A virtue is the habit of doing good (rather than individual acts) and avoiding evil (CCC 1803). There are two types of virtues–theological virtues (which refer to God and has Him as its object) (CCC 1812), and moral virtues (which deal with our moral lives and hence our actions, especially towards others) (CCC 1804). The theological virtues are faith, hope, and charity (1 Cor. 13:13). Faith is the virtue by which we believe all that God has revealed (CCC 1814). Hope is the virtue by which we trust that God will be faithful to His promise by granting us the means to obtain eternal life (CCC 1817). Charity is the virtue by which we love God above all things, and love our neighbor as ourselves for the love of God (CCC 1822).
There are many moral virtues, but there are four cardinal virtues (these are virtues upon which all other moral virtues hinge)–prudence, justice, fortitude, and temperance (CCC 1805). Prudence disposes us to make proper judgments on what and what not to do (CCC 1806). Justice disposes us to give to everyone what he deserves or what is due him (CCC 1807). Fortitude disposes us to do what is right in the face of difficulty (CCC 1808). Temperance disposes us to control our desires and sensual passions, and use them as God intends (CCC 1809).
The theological and moral virtues are commanded by God and expected from all men. But those who wish to aim at and attain perfection (Matt. 5:38), through striving for greater holiness (Heb. 12:14) observe the evangelical counsels–voluntary poverty, perpetual virginal chastity, and perfect obedience (CCC 915). These are the means by which religious (monks and nuns) follow in the footsteps of Jesus and Mary most closely. Religious take vows of poverty, chastity, and obedience, while priests make solemn promises of the latter two. Through voluntary poverty, the person usually relinquishes the ownership of all things, so that all their possessions belong to the religious community, and all that they own is what is needed, not what is desired: "If you wish to be perfect, go, sell what you have and give to the poor, and you will have treasure in heaven" (Matt. 19:21). Through perpetual virginal chastity, one abstains from all sexual activity (and also marriage and children) for "the sake of the kingdom" (Matt. 19:12). Through perfect obedience, a religious is obedient to his superior, because "he who listens to you [a religious superior–bishop or abbot] listens to me [Jesus}" (Luke 10:16); a religious follows the orders of his superior in every detail of his life. Priests also practice obedience, but to their bishop, and by extension, the pope, whose orders are less numerous and are not related to minor details of the priests' life or priesthood. The religious life and the married life are both good, but the consecrated single state is superior to the married state: "Everyone who has given up houses or brothers or sisters or father or mother or children or lands for the sake of my name will receive a hundred times more, and will inherit eternal life" (Matt. 19:29). However, this does not make religious holier than married people–holiness depends on what degree one fulfils his state in life, whether it be marriage, parenting, the priesthood, or the religious life.