Sources of obligation

Article 1157 of the Civil Code of the Philippines provides the sources of an obligation, to wit:

Art. 1157. Obligations arise from:

(1) Law;

(2) Contracts;

(3) Quasi-contracts;

(4) Acts or omissions punished by law; and

(5) Quasi-delicts. (1089a)

Law. Obligations arise when imposed by the law itself and cannot be presumed.[1] For example, an obligation arising from law is the payment of taxes.

Contracts. Obligations arise from the stipulation of the parties; it has the force of law and should be complied with in good faith.[2] For example, a contract of sale between a buyer and a seller in which the obligation arises.

Quasi-Contracts. Certain lawful, voluntary and unilateral acts give rise to the juridical relation of quasi-contract to the end that no one shall be unjustly enriched or benefited at the expense of another.[3] For example, X owed Y Php1,000. By mistake, X paid Y Php2,000. Y now has the obligation to return the excess payment because there was a mistake in the payment. This is called solutio indebiti.

Acts or Omissions Punishable by Law. Responsibility for fault or negligence under a quasi-delict (Art. 2176, CC) is entirely separate and distinct from the civil liability arising from negligence under the penal code. But the plaintiff cannot recover damages twice for the same act or omission of the defendant.[4] For example, under the Revised Penal Code murder and theft are prohibited. If you commit any of them, you will have the obligation to pay damages and fines or be put in jail.

Quasi-Delicts. Obligations arise from damages caused to another through an act or omission, there being fault or negligence but no contractual relations exist between the parties.[5] For example, X broke the car window of Y while playing basketball. In this case, X now has the obligation to pay the damage caused to Y due to X's act. 

[1] Art. 1158, Civil Code.

[2] Art. 1159, Civil Code.

[3] Art. 2142, Civil Code.

[4] Art. 2177, Civil Code.

[5] Art. 2176, Civil Code.