"Promises must be kept and contracts strictly observed to the extent that the commitments made in them are morally just. A significant part of economic and social life depends on the honoring of contracts between physical or moral persons - commercial contracts of purchase or sale, rental or labor contracts. All contracts must be agreed to and executed in good faith. Contracts are subject to commutative justice which regulates exchanges between persons and between institutions in accordance with a strict respect for their rights. Commutative justice obliges strictly; it requires safeguarding property rights, paying debts, and fulfilling obligations freely contracted. Without commutative justice, no other form of justice is possible."