Identity rule; res judicata

In cases involving res judicata, the parties and the causes of action are identical or substantially the same in the prior as well as the subsequent action. The judgment in the first action is conclusive as to every matter offered and received therein and as to any other matter admissible therein and which might have been offered for that purpose, hence said judgment is an absolute bar to a subsequent action for the same cause.

The bar extends to questions necessarily involved in an issue, and necessarily adjudicated, or necessarily implied in the final judgment, although no specific finding may have been made in reference thereto, and although such matters were directly referred to in the pleadings and were not actually or formally presented. Said prior judgment is conclusive in a subsequent suit between the same parties on the same subject matter, and on the same cause of action, not only as to matters which were decided in the first action, but also as to every other matter which the parties could have properly set up in the prior suit. (Arreza v. Diaz, Jr., G.R. No. 133113, August 30, 2001)