The Twenty Commandments
Although Franc Tremblay and Dawson Bethrick have shown time and again that the Ten Commandments are morally worthless, I think that an analysis of the textual source for these lists is supremely fascinating.
Casual references to the scriptural source for the Ten Commandments will usually mention two locations (Exodus 20 and Deuteronomy 5), but it's relatively rare to hear about the other place they're listed (Exodus 34). Usually, the reason for this is that although there's an obvious citation of the phrase "Ten Commandments," there isn't a recognizable list- at least, of the so-called orthodox version of the Commandments.
You see, looking a bit closer at Exodus 34 shows that there actually is a set of Ten Commandments therein- and there are even some that can be recognized, such as the command to worship only Yahweh (the name of the Hebrew deity), the prohibition against making any idols, and the command to observe the Sabbath. And yet, the other items in the list are strange, concerned primarily with Temple worship and cultic feasts.
In fact, if one were to dive a bit closer into the text of Exodus 34, and in fact, the larger surrounding corpus, one would find two parallel but slightly different narratives, laid end to end in Exodus, which indicate a human composition of the Pentateuch.
I performed such an analysis years ago just after I left Christianity, and have now posted this on my website. If you're interested, you can find it here.