Ten Commandments 
The Ten Commandments or Decalogue (10 words) was given by God on Mt. Horeb (also known as Mt. Sinai) to Moses around 1280 BC. They are the core of the moral teachings of Israel and have come down to Christianity as part of Divine Revelation. The Church in commenting on the Commandments sees in them the totality of the negative and positive moral law, the things we should not do, as well as the things we should do. This is to say, they embody the entire natural law, what reason can discover of morality from the nature of the world and man. However, as St. Thomas Aquinas noted, not every society, much less every man, discovers the entire natural law, so God has revealed it in the Commandments so it could be known with certainty by all men, of every society, and every age.

The Bible gives two versions of the Ten Commandments, in essential content identical, one in Exodus and another in Deuteronomy. The enumeration of the commandants (which is number one, which is two etc.) are traditional and neither contained in the texts nor obvious. The Catholic Church has traditionally used the Deuteronomy account and followed the division of the text given in the Septuagint, the Greek translation of the Scriptures made by second century BC Jews in Egypt and used by the early Church as its Old Testament. The Anglican Church and the Lutheran Church also use this account. The other Reformation churches use the Exodus listing, and adopted the Jewish enumeration of the Hebrew text. 

The Commandants are probably best known from the traditional formulas used in catechesis. 

Catholic

Protestant
I. I am the Lord your God: you shall not have strange gods before me. You shall not make for yourself a graven image.

I. Thou shalt have no other gods before me.
II. You shall not take the name of the Lord your God in vain. II. Thou shalt not take the name of the Lord thy God in vain.
III. Remember to keep holy the Lord's Day. III. Thou shalt not make unto thee any graven image.
IV. Honor your father and mother. IV. Remember the sabbath day to keep it holy.
V. You shall not kill. V. Honor thy father and thy mother.
VI. You shall not commit adultery. VI. Thou shalt not kill.
VII. You shall not steal VII. Thou shalt not commit adultery.
VIII. You shall not bear false witness against your neighbor. VIII. Thou shalt not steal.
IX. You shall not covet your neighbor's wife. IX.  Thou shalt not bear false witness against thy neighbor.
X. You shall not covet your neighbor's goods X. Thou shalt not covet thy neighbor's wife. Thou shalt not covet thy neighbors goods

 

Comparison of the full text

Catholic:
Deuteronomy 5:7-21

Protestant:
Exodus 20:3-17

I.  [7] You shall not have other gods besides me.  [8] You shall not carve idols for yourselves in the shape of anything in the sky above or on the earth below or in the waters beneath the earth;  [9] you shall not bow down before them or worship them. For I, the LORD, your God, am a jealous God, inflicting punishments for their fathers' wickedness on the children of those who hate me, down to the third and fourth generation  [10] but bestowing mercy, down to the thousandth generation, on the children of those who love me and keep my commandments.

 I.  [3] You shall not have other gods besides me.  

II. [4] You shall not carve idols for yourselves in the shape of anything in the sky above or on the earth below or in the waters beneath the earth;  [5] you shall not bow down before them or worship them.
For I, the LORD, your God, am a jealous God, inflicting punishment for their fathers' wickedness on the children of those who hate me, down to the third and fourth generation;  [6] but bestowing mercy down to the thousandth generation, on the children of those who love me and keep my commandments

Cf. Mt 4:10, 22:36-38; Mk 7:22
Commands: Adoration, prayer, sacrifice, promises, vows
Forbids: Idolatry, superstition, magic, divination (the occult), irreligion, atheism, agnosticism

II. [11]  You shall not take the name of the LORD, your God, in vain. For the LORD will not leave unpunished him who takes his name in vain.

III. [7]  You shall not take the name of the LORD, your God, in vain. For the LORD will not leave unpunished him who takes his name in vain. 

Cf. Mt 5:33-37; Acts 19:13-17; Col. 3:17; Mt 22:36-38 
Commands: Respect for God's Name, Saints, etc., confession of faith, promises and vows which honor God.
Forbids: Blasphemy, cursing and perjury 

III.    [12]  Take care to keep holy the sabbath day as the LORD, your God, commanded you.  [13] Six days you may labor and do all your work;  [14] but the seventh day is the sabbath of the LORD, your God. No work may be done then, whether by you, or your son or daughter, or your male or female slave, or your ox or ass or any of your beasts, or the alien who lives with you. Your male and female slave should rest as you do.  [15] For remember that you too were once slaves in Egypt, and the LORD, your God, brought you from there with his strong hand and outstretched arm. That is why the LORD, your God, has commanded you to observe the sabbath day.  

IV.   [8]  Remember to keep holy the sabbath day.  [9] Six days you may labor and do all your work,  [10] but the seventh day is the sabbath of the LORD, your God. No work may be done then either by you, or your son or daughter, or your male or female slave, or your beast, or by the alien who lives with you.  [11] In six days the LORD made the heavens and the earth, the sea and all that is in them; but on the seventh day he rested. That is why the LORD has blessed the sabbath day and made it holy.

Cf. Mk 2:27-28; Heb 4:9; Mt 22:36-38   
Commands: Keeping a Sabbath (Sunday for Christians), day of rest, prayer; by Church law: Mass.  
Forbids: Unnecessary work, non-observance of religious practice

IV.  [16]  Honor your father and your mother, as the LORD, your God, has commanded you, that you may have a long life and prosperity in the land which the LORD, your God, is giving you.  

V.  [12]  Honor your father and your mother, that you may have a long life in the land which the LORD, your God, is giving you.  

Cf. Mt 15:4-6, 19:19, 1 Cor 4:14-17; Eph 6:1-3; Mt 22:39-40; Rom 13:9
Commands: Respect, honor for parents (filial piety), obedience to them; also to parental figures in Church or state, patriotism; Duties of parents, Church and state toward members, esp. the duty of a human and religious education.  
Forbids: dishonor, disrespect, disobedience, neglect in old age etc. of parents, tyranny and corruption in government etc.

V.  [17]  You shall not kill.    

VI.  [13]  You shall not kill.  

Cf. Mt 19:18; Eph 4:31; Mt 22:39-40; Rom 13:9   
Commands: Respect for Life, material and spiritual health of self and others, permits legitimate self-defense of individuals and nations (just war), as well as capital punishment, respect for the bodies of the dead.  
Forbids: Murder, abortion, infanticide, euthanasia, suicide, sterilization, mutilation,  battery, unjustified anger, giving scandal, inordinate accumulation of armament, commerce in arms.

VI.  [18]  You shall not commit adultery. 

VII.  [14]  You shall not commit adultery. 

Cf. Mt 19:18; Mk 7:22; Eph 5:3-4; Mt 22:39-40; Rom 13:9.   
Commands: Respect for the marriage bed, use of sexual powers (chastity).
Forbids: Adultery, fornication, sexual acts preparatory to intercourse outside marriage, masturbation, homosexuality, pornography, prostitution, contraception, etc.

VII. [19]  You shall not steal. 

VIII.  [15]  You shall not steal.  

Cf. Mt 19:18; Mk 7:21; Eph 4:28; Mt 22:39-40; Rom 13:9.  
Commands: Respect for the possessions of others, restitution for injustices, respect for the common goods of humanity (resources, environment), a just economic order, just wages  (family wage) and working conditions, love for the poor (in imitation of God's preference for the poor and oppressed).   
Forbids: Stealing, vandalism, abuse, tax-evasion, copyright infringement etc., injustices against employees or employer. 

VIII.    [20]  You shall not bear dishonest witness against your neighbor.   

IX.  [16]  You shall not bear false witness against your neighbor.  

Mt 5:33, 19:18; Eph 4:25; Mt 22:39-40; Rom 13:9.  
Commands: Respect for other's good name (even the dead), truthfulness.   
Forbids: Detraction (true faults), calumny (false faults), gossip, rash judgment, contumacy, lying, violation of secrets. 

IX. [21a]  You shall not covet your neighbor's wife.  

X.  [17]  You shall not covet your neighbor's house. You shall not covet your neighbor's wife, nor his male or female slave, nor his ox or ass, nor anything else that belongs to him.

 X.   [21b]  'You shall not desire your neighbor's [goods] house or field, nor his male or female slave, nor his ox or ass, nor anything that belongs to him.

9th. Cf. Mt 5:27-28, 19:18; Eph 5:3-4; Mt 22:39-40; Rom 13:9.   
Commands: purity of heart, intention.   
Forbids: Desiring the wife of another, sexual thoughts and fantasies inconsistent with one's marital status.
10th. Cf. Mt 6:21, 19:18; Mk 7:22.    
Commands: purity of heart re: possessions of others.   
Forbids: avarice (greed), materialism.
 

Answered by Colin B. Donovan, STL

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