What caused Douglass to say, "I saw more clearly than ever the brutalizing effects of slavery upon both slave and slaveholder"

Frederick Douglass said this after witnessing a particularly brutal whipping of his Aunt Hester by his master, Captain Aaron Anthony. This traumatic event made him realize the dehumanizing and brutal nature of slavery, not only on the enslaved individuals but also on the slaveholders who perpetuated such violence. It strengthened his resolve to resist and speak out against the institution of slavery.