Duke Leto enters the training room. Why not? Everyone else is doing it.
Leto and Paul talk about how they are leaving for Arrakis tomorrow. The Duke tells his son that Arrakis, with its spice, Fremen, and connections to the CHOAM (Combine Honnete Ober Advancer Mercantile), can be beneficial to House Atreides. Of course, the Harkonnens will move against them.
Paul wonders why they are walking into a trap, but Leto tells him that "[k]nowing where the trap is—that's the first step to evading it" (6.32). Ah, clever Leto, very clever.
It seems that the Duke already knows that the Emperor has stockpiled spice and backed the House of Harkonnen with Sardaukar troops.
History Allusion Approaching: The Sardaukar come from Salusa Secundus, a planet conveniently abbreviated S.S. (6.49). This is Herbert's subtle (ahem) way of comparing the Sardaukar to the Nazi Schutzstaffel, also known as the S.S. In short, these are not the kind of people you want to hang out with on a Saturday night.
The Duke plans to counter the Sardaukar by negotiating with the Fremen. Why? Because if you lived on a planet like Arrakis, you'd be hard as nails. Scratch that. If you lived on a planet like Arrakis, you'd eat nails for a noon snack.
Next we come to talk of killing (ah, father-son bonding at its finest). The Duke warns his son that should the time come, he must be willing to kill in any way he can.
On a lighter note, Duke Leto wants his son to begin training in the ways of a Mentat. He won't force the issue, but he feels it will be valuable when Paul becomes duke.