What follows is the "in Brief" section of the Catechism of the Catholic Church for each of the Ten Commandments. They are a great resource for prayer and meditation in the pursuit of holiness.

First Commandment
I am the LORD your God: you shall not have strange Gods before me.
2133 "You shall love the Lord your God with all your heart, and with all your soul and with all your strength" (Deut 6:5).
2134 The first commandment summons man to believe in God, to hope in him, and to love him above all else.
2135 "You shall worship the Lord your God" (Mt 4:10). Adoring God, praying to him, offering him the worship that belongs to him, fulfilling the promises and vows made to him are acts of the virtue of religion which fall under obedience to the first commandment.
2136 The duty to offer God authentic worship concerns man both as an individual and as a social being.
2137 "Men of the present day want to profess their religion freely in private and in public" (DH 15).
2138 Superstition is a departure from the worship that we give to the true God. It is manifested in idolatry, as well as in various forms of divination and magic.
2139 Tempting God in words or deeds, sacrilege, and buying and selling of spiritual things are sins of irreligion forbidden by the first commandment.
2140 Since it rejects or denies the existence of God, atheism is a sin against the first commandment.
2141 The veneration of sacred images is based on the mystery of the Incarnation of the Word of God. It is not contrary to the first commandment.

Second Commandment
You shall not take the name of the LORD your God in vain.
2160 "O Lord, our Lord, how majestic is your name in all the earth" (Ps 8:1)!
2161 The second commandment enjoins respect for the Lord's name. The name of the Lord is holy.
2162 The second commandment forbids every improper use of God's name. Blasphemy is the use of the name of God, of Jesus Christ, of the Virgin Mary, and of the saints in an offensive way.
2163 False oaths call on God to be witness to a lie. Perjury is a grave offence against the Lord who is always faithful to his promises.
2164 "Do not swear whether by the Creator, or any creature, except truthfully, of necessity, and with reverence" (St. Ignatius of Loyola, Spiritual Exercises, 38).
2165 In Baptism, the Christian receives his name in the Church. Parents, godparents, and the pastor are to see that he be given a Christian name. The patron saint provides a model of charity and the assurance of his prayer.
2166 The Christian begins his prayers and activities with the Sign of the Cross: "in the name of the Father and of the Son and of the Holy Spirit. Amen."
2167 God calls each one by name (cf. Isa 43:1)

Third Commandment
Remember to keep holy the LORD'S Day.
2189 "Observe the sabbath day, to keep it holy" (Deut 5:12). "The seventh day is a sabbath of solemn rest, holy to the Lord" (Ex 31:15).
2190 The sabbath, which represented the completion of the first creation, has been replaced by Sunday which recalls the new creation inaugurated by the Resurrection of Christ.
2191 The Church celebrates the day of Christ's Resurrection on the "eighth day," Sunday, which is rightly called the Lord's Day.
2192 "Sunday . . . is to be observed as the foremost holy day of obligation in the universal Church". "On Sundays and other holy days of obligation the faithful are bound to participate in the Mass".
2193 "On Sundays and other holy days of obligation the faithful are bound . . . to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord's Day, or the proper relaxation of mind and body".
2194 The institution of Sunday helps all "to be allowed sufficient rest and leisure to cultivate their familial, cultural, social, and religious lives".
2195 Every Christian should avoid making unnecessary demands on others that would hinder them from observing the Lord's Day.

Fourth Commandment
Honor your father and your mother.
2247 "Honor your father and your mother" (Deut 5:16; Mk 7:10).
2248 According to the fourth commandment, God has willed that, after him, we should honor our parents and those whom he has vested with authority for our good.
2249 The marital community is established upon the covenant and consent of the spouses. Marriage and family are ordered to the good of the spouses, to the procreation and the education of children.
2250 "The well-being of the individual person and of both human and Christian society is closely bound up with the healthy state of conjugal and family life".
2251 Children owe their parents respect, gratitude, just obedience, and assistance. Filial respect fosters harmony in all of family life.
2252 Parents have the first responsibility for the education of their children in the faith, prayer, and all the virtues. They have the duty to provide as far as possible for the physical and spiritual needs of their children.
2253 Parents should respect and encourage their children's vocations. They should remember and teach that the first calling of the Christian is to follow Jesus.
2254 Public authority is obliged to respect the fundamental rights of the human person and the conditions for the exercise of his freedom.
2255 It is the duty of citizens to work with civil authority for building up society in a spirit of truth, justice, solidarity, and freedom.
2256 Citizens are obliged in conscience not to follow the directives of civil authorities when they are contrary to the demands of the moral order. "We must obey God rather than men" (Acts 5:29).
2257 Every society's judgments and conduct reflect a vision of man and his destiny. Without the light the Gospel sheds on God and man, societies easily become totalitarian.

Fifth Commandment
You  Shall not kill
2318 "In [God's] hand is the life of every living thing and the breath of all mankind" (Job 12:10).
2319 Every human life, from the moment of conception until death, is sacred because the human person has been willed for its own sake in the image and likeness of the living and holy God.
2320 The murder of a human being is gravely contrary to the dignity of the person and the holiness of the Creator.
2321 The prohibition of murder does not abrogate the right to render an unjust aggressor unable to inflict harm. Legitimate defense is a grave duty for whoever is responsible for the lives of others or the common good.
2322 From its conception, the child has the right to life. Direct abortion, that is, abortion willed as an end or as a means, is a "criminal" practice (GS 27 § 3), gravely contrary to the moral law. The Church imposes the canonical penalty of excommunication for this crime against human life.
2323 Because it should be treated as a person from conception, the embryo must be defended in its integrity, cared for, and healed like every other human being.
2324 Intentional euthanasia, whatever its forms or motives, is murder. It is gravely contrary to the dignity of the human person and to the respect due to the living God, his Creator.
2325 Suicide is seriously contrary to justice, hope, and charity. It is forbidden by the fifth commandment.
2326 Scandal is a grave offense when by deed or omission it deliberately leads others to sin gravely.
2327 Because of the evils and injustices that all war brings with it, we must do everything reasonably possible to avoid it. The Church prays: "From famine, pestilence, and war, O Lord, deliver us."
2328 The Church and human reason assert the permanent validity of the moral law during armed conflicts. Practices deliberately contrary to the law of nations and to its universal principles are crimes.
2329 "The arms race is one of the greatest curses on the human race and the harm it inflicts on the poor is more than can be endured" (GS 81 § 3).
2330 "Blessed are the peacemakers, for they shall be called sons of God" (Mt 5:9).

Sixth Commandment
You shall not commit adultery
2392 "Love is the fundamental and innate vocation of every human being" (FC 11).
2393 By creating the human being man and woman, God gives personal dignity equally to the one and the other. Each of them, man and woman, should acknowledge and accept his sexual identity.
2394 Christ is the model of chastity. Every baptized person is called to lead a chaste life, each according to his particular state of life.
2395 Chastity means the integration of sexuality within the person. It includes an apprenticeship in self-mastery.
2396 Among the sins gravely contrary to chastity are masturbation, fornication, pornography, and homosexual practices.
2397 The covenant which spouses have freely entered into entails faithful love. It imposes on them the obligation to keep their marriage indissoluble.
2398 Fecundity is a good, a gift and an end of marriage. By giving life, spouses participate in God's fatherhood.
2399 The regulation of births represents one of the aspects of responsible fatherhood and motherhood. Legitimate intentions on the part of the spouses do not justify recourse to morally unacceptable means (for example, direct sterilization or contraception).
2400 Adultery, divorce, polygamy, and free union are grave offenses against the dignity of marriage.

Seventh Commandment
You shall not steal
2450 "You shall not steal" (Ex 20:15; Deut 5:19). "Neither thieves, nor the greedy . . ., nor robbers will inherit the kingdom of God" (1 Cor 6:10).
2451 The seventh commandment enjoins the practice of justice and charity in the administration of earthly goods and the fruits of men's labor.
2452 The goods of creation are destined for the entire human race. The right to private property does not abolish the universal destination of goods.
2453 The seventh commandment forbids theft. Theft is the usurpation of another's goods against the reasonable will of the owner.
2454 Every manner of taking and using another's property unjustly is contrary to the seventh commandment. The injustice committed requires reparation. Commutative justice requires the restitution of stolen goods.
2455 The moral law forbids acts which, for commercial or totalitarian purposes, lead to the enslavement of human beings, or to their being bought, sold or exchanged like merchandise.
2456 The dominion granted by the Creator over the mineral, vegetable, and animal resources of the universe cannot be separated from respect for moral obligations, including those toward generations to come.
2457 Animals are entrusted to man's stewardship; he must show them kindness. They may be used to serve the just satisfaction of man's needs.
2458 The Church makes a judgment about economic and social matters when the fundamental rights of the person or the salvation of souls requires it. She is concerned with the temporal common good of men because they are ordered to the sovereign Good, their ultimate end.
2459 Man is himself the author, center, and goal of all economic and social life. The decisive point of the social question is that goods created by God for everyone should in fact reach everyone in accordance with justice and with the help of charity.
2460 The primordial value of labor stems from man himself, its author and beneficiary. By means of his labor man participates in the work of creation. Work united to Christ can be redemptive.
2461 True development concerns the whole man. It is concerned with increasing each person's ability to respond to his vocation and hence to God's call (cf. CA 29).
2462 Giving alms to the poor is a witness to fraternal charity: it is also a work of justice pleasing to God.
2463 How can we not recognize Lazarus, the hungry beggar in the parable (cf. Lk 17:19-31), in the multitude of human beings without bread, a roof or a place to stay? How can we fail to hear Jesus: "As you did it not to one of the least of these, you did it not to me" (Mt 25:45)?

Eighth Commandment
You shall not bear false witness against your neighbor.
2504 "You shall not bear false witness against your neighbor" (Ex 20:16). Christ's disciples have "put on the new man, created after the likeness of God in true righteousness and holiness" (Eph 4:24).
2505 Truth or truthfulness is the virtue which consists in showing oneself true in deeds and truthful in words, and guarding against duplicity, dissimulation, and hypocrisy.
2506 The Christian is not to "be ashamed of testifying to our Lord" (2 Tim 1:8) in deed and word. Martyrdom is the supreme witness given to the truth of the faith.
2507 Respect for the reputation and honor of persons forbids all detraction and calumny in word or attitude.
2508 Lying consists in saying what is false with the intention of deceiving one's neighbor.
2509 An offense committed against the truth requires reparation.
2510 The golden rule helps one discern, in concrete situations, whether or not it would be appropriate to reveal the truth to someone who asks for it.
2511 "The sacramental seal is inviolable" (CIC, can. 983 § 1). Professional secrets must be kept. Confidences prejudicial to another are not to be divulged.
2512 Society has a right to information based on truth, freedom, and justice. One should practice moderation and discipline in the use of the social communications media.
2513 The fine arts, but above all sacred art, "of their nature are directed toward expressing in some way the infinite beauty of God in works made by human hands. Their dedication to the increase of God's praise and of his glory is more complete, the more exclusively they are devoted to turning men's minds devoutly toward God" (SC 122).

Ninth Commandment
You shall not covet your neighbor's wife.
2528 "Everyone who looks at a woman lustfully has already committed adultery with her in his heart" (Mt 5:28).
2529 The ninth commandment warns against lust or carnal, strong sexual desire.
2530 The struggle against carnal lust involves purifying the heart and practicing temperance.
2531 Purity of heart will enable us to see God: it enables us even now to see things according to God.
2532 Purification of the heart demands prayer, the practice of chastity, purity of intention and of vision.
2533 Purity of heart requires the modesty which is patience, decency, and discretion. Modesty protects the intimate center of the person.

Tenth Commandment
You shall not covet your neighbor's goods.
2551 "Where your treasure is, there will your heart be also" (Mt 6:21).
2552 The tenth commandment forbids greed arising from a passion for riches and their attendant power.
2553 Envy is sadness at the sight of another's goods and the immoderate desire to have them for oneself. It is a capital sin.
2554 The baptized person combats envy through good-will, humility, and abandonment to the providence of God.
2555 Christ's faithful "have crucified the flesh with its passions and desires" (Gal 5:24); they are led by the Spirit and follow his desires.
2556 Detachment from riches is necessary for entering the Kingdom of heaven. "Blessed are the poor in spirit."
2557 "I want to see God" expresses the true desire of man. Thirst for God is quenched by the water of eternal life (cf. Jn 4:14)