Both sides agreed with the words.
Although there was disagreement when ratifying the Constitution in favor of a central, Federalist, or decentralized, anti-federalist government, both sides, each with its own motives, were concerned with individual freedoms.
For the Federalists, building a government based on popular sovereignty would give legitimacy to the Government.
The anti-federalists wanted to sufficiently protect the rights of individuals and states.
In this context, and based on Illuminist ideals, the letter states in its first paragraph that "all power emanates from the people," contrary to what was previously advocated for a "power emanating from God."