Expound on the meaning of "juridical necessity" as it is used

in Art. 1156 in connection with Art. 1423. Clarify how this concept relates with extinctive prescription as it is provided in Arts. 1139 and 1424. Provide your own simple example of a contract that illustrates your explanation.

Elaborate on how extra-contractual obligations (i.e., those that arise from quasi-contracts and quasi-delicts) essentially differ from contractual obligations (i.e., those that arise from contracts). Include a brief discussion on the nature of quasi-contracts (Art. 2142) and quasi-delicts (Art. 2176) in your answer.

Article 1156: An obligation is a juridical necessity to give, to do or not to do.

Article 1423: Obligations are civil or natural. Civil obligations give a right of action to compel their performance. Natural obligations, not being based on positive law but on equity and natural law, do not grant a right of action to enforce their performance, but after voluntary fulfillment by the obligor, they authorize the retention of what has been delivered or rendered by reason thereof. Some natural obligations are set forth in the following articles.

Article 1139. Actions prescribe by the mere lapse of time fixed by law.

Article 1424. When a right to sue upon a civil obligation has lapsed by extinctive prescription, the obligor who voluntarily performs the contract cannot recover what he has delivered or the value of the service he has rendered.

Article 2142. 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.

Article 2176. Whoever by act or omission causes damage to another, there being fault or negligence, is obliged to pay for the damage done. Such fault or negligence, if there is no pre-existing contractual relation between the parties, is called a quasi-delict and is governed by the provisions of this Chapter. (1902a)

those are all it is from the Civil Code of the PH