Darkness. The brothers of Joseph have murdering thoughts, hardened hearts, and are hypocrites. But most important, Jacob is without hope, even if God revealed him that Joseph will be a great man one day, so he couldn't die. But he believed not.
Great Sermon! There is a book and other series by Dr. Sproul that would add to this type content such as "Christian Worldview" & "The Christian Mind". You can check the store at ligonier.org for these and others (look in the Philosophy/Apologetics section).
Last episode If you want to continue, post-modern philosophy is covered by Dominic Smart (of Gilcomston) in an excellent presentation you can find on SermonAudio. RC Sproul's series is an excellent introduction to philosophy, and I highly recommend it. Sproul does a good job boiling down some of the most essential points of thousands of years and hundreds of philosophers into interesting, memorable, and listenable segments. I've always thought it unusual that Sproul doesn't even mention post-modern philosophers like Foucault and Derrida. Smart's sermon on post-modernism is of the same high quality, and is a natural extension of Sproul's series, if you want to tie it all together.
Fantastic series This series on philosophy is very well done. It gives you a good overview of the subject without getting bogged down in details. If you're curious about philosophy, I highly recommend it. I'm glad they're putting it on sermonaudio for homeschoolers, etc to listen to. Sproul has a good book of the same name ("The Consequence Of Ideas") that has a bibliography of primary and a few good secondary sources.