Immutability, inalterability of final judgment

In the case of Pinewood Marine v. EMCO Plywood Corp., et al.,[1] the Supreme Court found that the Court of Appeals did not err in denying Pinewood's Motion for Reconsideration seeking for the reinstatement of the latter's appeal. The Decision of the RTC, dated May 14, 1997, had long become final as far as Pinewood is concerned. In PCI Leasing and Finance, Inc. v. Milan, et al.,[2] the Supreme Court reiterated the principle that:
A judgment becomes "final and executory" by operation of law. Finality becomes a fact when the reglementary period to appeal lapses and no appeal is perfected within such period. As a consequence, no court (not even the Supreme Court) can exercise appellate jurisdiction to review a case or modify a decision that has became final.

When a final judgment is executory, it becomes immutable and unalterable. It may no longer be modified in any respect either by the court which rendered it or even by this [Supreme] Court. The doctrine is founded on considerations of public policy and sound practice that, at the risk of occasional errors, judgments must become final at some definite point in time.

The doctrine of immutability and inalterability of a final judgment has a two-fold purpose: (1) to avoid delay in the administration of justice and thus, procedurally, to make orderly the discharge of judicial business and (2) to put an end to judicial controversies, at the risk of occasional errors, which is precisely why courts exist. Controversies cannot drag on indefinitely. The rights and obligations of every litigant must not hang in suspense for an indefinite period of time.[3]

[1] G.R. No. 179789, June 17, 2015. 
[2] 631 Phil. 257 (2010).
[3] Id. at 277-278, citing Social Security System v. Isip, 549 Phil. 112, 116 (2007).