There's a detail I have to explain here at the outset. There are two different common enumerations of the “Ten Commandments”. They both refer to Exodus 20, but divide one commandment from another differently at two points. In the enumeration used by Catholics and Lutherans (and possibly others), Exodus 20:4-6, which forbids making and worshiping idols, is regarded as explanatory of verse 3, which forbids having other gods. On the other hand, Exodus 20:16 and 17, which, respectively, forbid coveting and forbid coveting a list of items are separated into two commandments. The enumeration I'll be using, common among many Protestants (not my reason for using this enumeration, though), considers Exodus 20:4-6 to be a separate commandment from verse 3, and considers Exodus 20:16-17 to be one commandment, with verse 17 providing examples to explain verse 16. As a child, growing up in a Lutheran church, considering Exodus 20:16 and 17 to be two separate commandments didn't make sense to me. And if you think about Exodus 20:3 and Exodus 20:4-6 as circles in elementary school Mathematics Venn Diagrams, the two circles intersect substantially, but not entirely. Exodus 20:3 forbids having other gods, whether physical idols or gods not represented physically. Exodus 20:4-6 forbids idols, whether of other gods, such as in Egypt or those used by the Canaanites, or physical representations of the true God.
Well, that was long-winded! Why am I doing this? First, while Christians' salvation does not depend on keeping the law, right and wrong did not change. And if Christians truly love God, disobeying Him is something they should desire to avoid, because of that love. Second, and to me oddly, basic teaching about right and wrong seems scarce in some Evangelical circles.
In succeeding posts, each about one of the commandments, I'll include the relevant verse plus Martin Luther's Small Catechism explanations (http://bookofconcord.org/smallcatechism.php#tencommandments - which seemed rather good to me when I was learning the Ten Commandments) along with my own comments. Since I haven't written these reflections in advance of this post, I won't promise these to be daily or not to publish other blog posts between.