The primary arguments that these two men made were centered on the idea that the Constitution made the federal government too strong. They feared that change and thought that it was illegal and unwarranted.
For example, Henry argued that there was no basis for trying to make a union of the people rather than of the states. He argued that the convention had had no right to make such a union that was based on the people. He said that such a union would create a single consolidated government. Mason agreed with Henry’s qualms. He said that national government like that would completely destroy the state governments.
The point of all these worries was that the federal government was more likely to be tyrannical. Men like Henry and Mason felt that the federal government was farther from the people and therefore less likely to care about guarding their rights.