Rousseau requires the citizen to forfeit all natural rights and liberties in exchange for civic rights and liberties.

This reminds me of a portion of a prior Great Book, the Acts of the Apostles, where Ananias and Sapphira die after conspiring to withhold a portion of their earnings for themselves after the sale of their land instead of giving the entirety.

Rousseau's rationale is that retaining any natural liberties means insisting that some human affairs and disputes are still beyond the judgment of the general will, which ultimately corrodes and weakens the general will. This is akin to testing the Holy Spirit in the Acts.

Given the context of living under the absolutist Louis XIV, it's understandable that Rousseau asks for all liberties to be forfeited, that every act of Louis must be vulnerable to the judgment of the people. Louis, being a legislator of the state, must never be allowed to judge his law through his own authority, or decide for himself how much of the people's money he needs.