The principle of Pacta Sunt Servanda, or the Obligation of Contracts, signifies that obligations arising from contracts have the force of law between the contracting parties. This means that a valid contract creates binding legal obligations upon the parties who entered into it.

Key Elements and Effects

• Force of Law: Contracts create obligations that are as binding as laws between the specific parties involved.
• Compliance and Good Faith: Obligations arising from contracts should be complied with, and this compliance must be done in good faith.
• Not Subject to Unilateral Will: The validity or compliance of a contract generally cannot be left to the sole will of one of the parties.
• Effect on Parties, Assigns, and Heirs: Contracts generally take effect between the contracting parties, their assigns, and heirs.

This principle is explicitly recognized in contract law and is referred to as the obligatory force of contracts.