How does Heathcliff describe his duties to and expectations of his son in Chapter 20?

Heathcliff says, "my son is prospective owner of your place, and I should not wish him to die till I was certain of being his successor. Besides, he's mine, and I want the triumph of seeing my descendant fairly lord of their estates: my child hiring their children to till their fathers' land for wages. That is the sole consideration which can make me endure the whelp: I despise him for himself, and hate him for the memories he revives!"