From religioustolerance.org
I can't find any other source for the veracity of the slave reference. There are thousands of words written about stealing in general, how can they have forgotten the original meaning? I know about the confusion about which commandments are the supposed genuine ones, but, as these are the most well known, what of this interpretation?8th Commandment; Verse 15 "Thou shalt not steal."
"...this Commandment has been interpreted to refer to only one kind of theft; namely, to someone who kidnaps a person, forces him or her to work for him, and then sells him or her into slavery. This, like the previous prohibitions mentioned in the verse, murder and adultery, is a Capital Crime; that is, punishable by the death-penalty." 2 Since slavery has now been abolished in North America, this commandment is no longer applicable.
In modern times, the commandment is interpreted to mean the stealing of any piece of property. This is not directly related to its original meaning.
The Westminster Larger Catechism includes: "The covetousness; inordinate prizing and affecting worldly goods... envying at the prosperity of others; as likewise idleness, prodigality, wasteful gaming..."