“Covenants, without the sword, are but words, and of no strength to secure a man at all.”Thomas Hobbes · Leviathan · 1651 · Partea a II-a, capitolul 17
A promise without the power to enforce it is just words on paper.
Hobbes starts from a claim about human nature: everyone has a right to everything, and a promise can be broken whenever breaking it pays. A pact holds only if both parties fear the consequences, and that fear must come from a common power able to punish. Private contracts are therefore not enough without a state to enforce them. A plain example: a dispute between two states with no strong arbiter is settled by force, not by the signed text.
Hobbes leaves us a harder question than it seems: fear works only if the sanction is credible. A law can exist on paper, but if nobody applies it quickly, the promise becomes just a word again. Think of a neighbor who borrows your tool and promises to return it. If the whole neighborhood knows he honors nothing, the fear of shame binds him better than a written contract. The power that guarantees must not only be strong, but seen as able to act. Credibility, not brute force, keeps an agreement alive. But what happens when the powerful guarantors themselves fall out with each other?
Why it matters The line helps anyone negotiating contracts, treaties, or partnerships ask the practical question: who actually enforces the penalty if the other side breaks its word?