Augustus expresses his disgust for Henry's ownership of a slave on page 138 in the first Amistad paperback edition published in 2004.
When Henry tells his parents that he has help on his property, they think that he's hired help at first. They ask whether it's Charles, Millard, or Free Buddy. However, he tells them that he purchased his own man at a low price from Master Robbins. The man's name is Moses. Henry says that he's a good worker with a lot of years left.
Augustus and Mildred are shocked. Augustus can't believe it at first, saying, "You mean to tell me you bought a man and he yours now? You done bought him and you didn't free that man? You own a man, Henry?" Mildred asks him why. Henry doesn't even understand why they're upset at first and then says that no one ever taught him that owning slaves was wrong.
Augustus insists that you shouldn't have to be taught such a thing. He says:
"I promised myself when I got this little bit of land that I would never suffer a slaveowner to set foot on it. Never." He put his hand momentarily to his mouth and then tugged at his beard. "Of all the human beins on God’s earth I never once thought the first slaveowner I would tell to leave my place would be my own child. I never thought it would be you. Why did we ever buy you offa Robbins if you gon do this? Why trouble ourselves with you bein free, Henry? You could not have hurt me more if you had cut off my arms and my legs."
The two men fight and Augustus hits Henry with a stick. He tells him that's how a slave feels. Henry breaks the stick and says that's how a master feels. Then he saddles his horse and leaves.