Henry is calling for a revolution. By stating "Is life so dear, or peace so sweet, at to be purchased at the price of chains and slavery?" he points out that the fear of dying and the fear of war is not worth trading ones freedom, but rather one should choose freedom over a bandaged living and state of peace.
He is stating that the matter is more deeper than bodies, more soulful and more what matters on the inside with our souls. "Gorvern your own bodies" referring to not an actual body and its organs but what is inside a body deeply soulfully.
