The Ten Commandments are often held, especially by Biblical fundamentalists, to be the basis of modern law. This point of view is questionable, however, as the commandments include a number of items which are not generally addressed by modern law; it is probably more fair to say that the Ten Commandments formalized a number of key concepts which are still regarded as important today, to varying degrees, alongside a number of rules which are only meaningful in a religious context (and not enforced or even recognized by law in any modern societies).
From Exodus Chapter 20:
- 1a. I am the LORD thy God, who brought thee out of the land of Egypt, out of the house of bondage.
- 1b. Thou shalt have no other gods before Me.
- 2a. Thou shalt not make unto thee a graven image, nor any manner of likeness, of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth;
- 2b. thou shalt not bow down unto them, nor serve them; for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate Me; and showing mercy unto the thousandth generation of them that love Me and keep My commandments.
- 3. Thou shalt not take the name of the LORD thy God in vain; for the LORD will not hold him guiltless that taketh His name in vain.
- 4. Remember the sabbath day, to keep it holy. Six days shalt thou labour, and do all thy work; but the seventh day is a sabbath unto the LORD thy God, in it thou shalt not do any manner of work, thou, nor thy son, nor thy daughter, nor thy man-servant, nor thy maid-servant, nor thy cattle, nor thy stranger that is within thy gates; for in six days the LORD made heaven and earth, the sea, and all that in them is, and rested on the seventh day; wherefore the LORD blessed the sabbath day, and hallowed it.
- 5. Honour thy father and thy mother, that thy days may be long upon the land which the LORD thy God giveth thee.
- 6. Thou shalt not murder.
- 7. Thou shalt not commit adultery.
- 8. Thou shalt not steal.
- 9. Thou shalt not bear false witness against thy neighbour.
- 10. Thou shalt not covet thy neighbour's house; thou shalt not covet thy neighbour's wife, nor his man-servant, nor his maid-servant, nor his ox, nor his ass, nor any thing that is thy neighbour's.
Arguably basic to modern law
Among those concepts formalized by the Commandments which are also basic to most modern law and ethics are:
- (6) Don't murder
- (8) Don't steal
- (9) Don't make false claims about other people (widening the concept of "neighbor" somewhat; this commandment can arguably be generalized further to "don't lie")
Arguably basic to modern morality but not law
Some further concepts which are more or less ensconced in popular morality but less universally backed up by law (if at all):
- (5) Respect your parents
- (7) If you are married, having sex with someone else is wrong
- (10) Jealousy and envy are undesirable
Strictly religious in nature and not reliably observed or agreed upon
- (1) God is Chief God because He says so (interesting implication that there are other gods who might try to command our loyalty...)
- (2) Graven images are forbidden (definition of "graven image" still widely debated; Moslems observe the strictest interpretation, i.e. representational art)
- (3) No taking of God's name in vain, which is widely interpreted as "no cursing in God's name"
- (4) No working on the Sabbath (though it remains unclear whether this is Saturday, Sunday, or what). This was once widely ensconced in law, but today it remains largely as (1) the day when Christians most often attend Church, and (2) the day of the week when businesses are the least likely to be open.
Items 1 and 2 are in directly in contradiction of much modern law, including the US Constitution which establishes freedom of religion (you can worship whatever god(s) you like, or no god at all) and freedom of speech (you can draw pictures of anything you like); item 3 is also arguably in contradiction of both freedoms, though most of the time it seems to fall within the realm of obscenity, which is not protected in some venues.
Item 4 (or anything like it) is only respected within the most extreme religious totalitarian states, and is not in accordance with a modern enlightened view of government.
In the United States, the Ten Commandments have been at the center of a number of conflicts between religion and the doctrine of separation of church and state. It is often claimed by religious groups that US law is based on the Commandments, but this is not true; US laws were informed by many sources, including Roman and Byzantine laws, the Napoleonic Code, and European Common Law. Many of these systems of law had religious components, but those features were not only discarded by the US founding fathers but explicitly barred (by the separation of church and state laid out in the US constitution) from being re-introduced in the future. 
- The Ten Commandments is only one of several sets of moral systems found in the Bible; others include the Noahide Laws and the Levitican Laws.
dKosopediano article (as of 2008-03-13) SourceWatchno article (as of 2008-03-13)