Final answer:
Toussaint Louverture expresses the irreversible dedication of free men to maintain their liberty, vehemently rejecting any possibility of returning to slavery.
Step-by-step explanation:
Toussaint Louverture's central idea in his letter to the French Directory is that men who have experienced freedom will never accept the return to enslavement. Having broken the chains of slavery, they would sacrifice anything to maintain their liberty, and the same force that had liberated them would not be the one to re-enslave them. He speaks with fervor about the irreversible shift in consciousness and determination among his people, insisting that they have faced danger to gain their freedom and will confront death to keep it. The letter further emphasizes the importance of maintaining independence and sends a clear message that any attempts to re-impose slavery would be met with the fiercest of resistance.