From his essay, The State vs. Liberty:
“Taxation is theft, purely and simply even though it is theft on a grand and colossal scale which no acknowledged criminals could hope to match. It is a compulsory seizure of the property of the State’s inhabitants, or subjects.”
If taxation isn’t theft, then the implication is that the government owns every bit of your property, allowing you to keep what you currently have as a privilege. In other words, the master/slave dynamic.