Before us is a petition for review seeking the annulment of the decision of respondent Court of Appeals in CA-G.R. SP No. 16527.

The relevant facts of the case, as disclosed by the record, are as follows:

On January 17, 1979, private respondents, by themselves and through their predecessors-in-interest, filed complaints docketed as Civil Cases No. 630 and No. 631 of the Municipal Trial Court of Taytay, Rizal, for recovery of portions of a parcel of land located at Sitio Sampalucan, Barangay San Isidro, Taytay, Rizal, against David Palmenco, Chayong Rabino, Felix Magpili, Fisco Obrero, Herminio Simon, Oscar Santos, Gerry Degra, Tino Balinas, Terio Salinas, Alicia Baltazar, Remy Rosario, Diony del Rosario, Arturo del Rosario, Rodolfo Ordonio, Rogelio Yanga, Ignas Rabino, Primitivo Rodrigo, Nicolas Tamayo, Victor Achinges, Pepito Barbarin, Carlito Cielo, Aquino Advincula, Juanito Celis, Teresa Fulgera, Florencio Borja, Fidel Aguinaldo, Nestor Subia, Manuel Carlos, Cornelio Depano, Rufino Santos and Jose Labaguin (hereinafter referred to as David Palmenco, et al.).

Petitioners, although occupants of portions of the subject parcel of land in Civil Cases No. 630 and No. 631, were not impleaded as defendants in said cases.

On December 29, 1983, the Municipal Trial Court rendered a joint decision in the afore-mentioned cases, the dispositive portion of which reads:

WHEREFORE, decision is hereby rendered in the above-entitled cases sentencing the defendants David Palmenco, Chayong Rabino, Felix Magpili, Fisco Obrero, Herminio Simon, Oscar Santos, Gerry Degra, Tino Balinas, Terio Salinas, Alicia Baltazar, Remy Rosario, Diony del Rosario, Arturo del Rosario, Hipolito Rosal, Oscar Domingo, Rodolfo Ordonio, Rogelio Yanga, Ignas Rabino, Primitivo Rodrigo, Nicolas Tamayo, Victor Achinges, Pepito Barbarin, Carlito Cielo, Aquino Advincula, Juanito Celis, Teresa Fulgera, Florencio Borja, Fidel Aguinaldo, Nestor Subia, Manuel Carlos, Cornelio Depano, Rufino Santos, and Jose Libaguin, all of them, to vacate the premises in question and to restore the possession thereof of the plaintiffs; to pay the plaintiffs the sum of P6,000.00 as attorney's fees and the costs of the suit. (p. 73, Rollo)

On May 17, 1985, upon motion by private respondents, the Municipal Trial Court of Taytay, Rizal, issued a writ of execution directing the defendants in said cases to vacate subject parcel of land. Said defendants resisted the enforcement of the writ of execution on the ground that they had filed with the Bureau of Lands a complaint, docketed as B.L. Claim No. 625, against private respondents, and that the Director of Lands in said B.L. Claim No. 625 rendered a decision on September 18, 1986, the dispositive portion of which reads as follows:

. . . Accordingly, they shall, upon subdivision survey and approval thereof at their own expense, file within sixty (60) days from such approval appropriate public land application[s], otherwise, they shall lose the right of preference. Likewise, the claim of claimants-respondents to the areas occupied by them is sustained and they are hereby allowed to file within the same period after approval of the subdivision survey appropriate public land [applications] failure of which they shall lose their right of preference. (p. 74, Rollo)

To abate the execution, defendants David Palmenco, et al., filed a petition for certiorari, prohibition and injunction, docketed as AC-G.R. SP No. 05934 of the Intermediate Appellate Court (now Court of Appeals) praying, inter alia, that the decision rendered and the writ of execution issued in Civil Cases No. 630 and No. 631 be annulled and set aside. On April 26, 1985, respondent court dismissed the petition (Annex D, Memorandum of Private Respondents, p. 121, Rollo). The decision in SP No. 05934 having become final, the Municipal Trial Court issued on September 18, 1985 an order for the issuance of an alias writ of execution.

On October 3, 1985, David Palmenco, et al., the defendants in Civil Cases No. 630 and 631, filed another petition for certiorari, prohibition and injunction with the Regional Trial Court, Antipolo, Rizal, docketed as Civil Case No. 729-A, seeking to annul among others, said order of September 18, 1985 authorizing the issuance of a writ of execution.

On November 11, 1985, the Regional Trial Court of Antipolo, Rizal, rendered a decision in Case No. 729-A denying and dismissing the petition (See Decision of Court of Appeals in CA-G.R. SP No. 08124, p. 122, Rollo).

Their motion for reconsideration having been denied, said defendants filed another petition for certiorari, prohibition and injunction, docketed as CA-G.R. SP No. 08124 of respondent Court of Appeals, praying (a) to set aside the decision dated November 11, 1985 in Civil Case No. 729-A, (b) to set aside the alias writ of execution issued by the Municipal Trial Court in Civil Cases No. 630 and 631, the levy on execution dated November 22, 1985 and the Certificate of Sale both issued by the Deputy Regional Sheriff in said Civil Cases No. 630 and 631, and (c) to enjoin the Municipal Judge from issuing an alias writ of execution and a writ of demolition (See Decision of Court of Appeals in CA-G.R. SP No. 08124, supra). It is to be noted that this is the second time that this case was brought to the Court of Appeals. The first one was SP No. 05934, aforementioned.

On December 24, 1986, the Court of Appeals promulgated its decision in SP No. 08124 dismissing the petition (Annex E of Memorandum for Private Respondents, pp. 122-128, Rollo). A motion for reconsideration was filed by petitioners therein but on December 15, 1988, the Court of Appeals issued a resolution denying the motion for reconsideration (Annex F, Memorandum for Private Respondents, pp. 130-133, Rollo).

Petitioners filed in Civil Cases No. 630 and No. 631 an opposition dated November 27, 1986 (pp. 134-136, Rollo of CA-G.R. SP No. 16527), to the issuance of a writ of demolition.

On December 1, 1988, the other occupants of the subject parcel of land in Civil Cases No. 630 and 631, petitioners herein, filed an action for damages, docketed as Civil Case No. 1243 of the Regional Trial Court of Antipolo, Rizal, against respondents (1) Marina Cruz and (2) Antonio Cruz and (3) Eduardo Cruz, (4) Concepcion Cruz, (5) Teresita Cruz, (6) Mario Jose, (7) Mariano Gongora, (8) Hector Jose, (9) Juan S.P. Herros and (10) Pio E. Martinez, in his capacity as Ex-Officio Sheriff of the Regional Trial Court of Antipolo, Rizal (See Decision of Court of Appeals in CA-G.R. SP No. 16527, p. 33, Rollo).

On December 1, 1988, petitioners filed another action docketed as Civil Case No. 1311-A with the Regional Trial Court of Antipolo, Rizal, for annulment of the writ of demolition with damages against private respondents (1) Adora Cruz, (2) Antonio Cruz, and (3) Ruben Gongora, and (4) Eduardo Cruz, (5) Concepcion Cruz, (6) Teresita Cruz, (7) Mario Jose, (8) Mariano Gongora, (9) Hector Jose, (10) Pio Martinez, (11) Juan S.P. Herras; and (12) the Honorable Dominador Domingo (Petition, p. 9, Rollo).

On the same date, David Palmenco, et al., the defendants in Civil Cases No. 630 and 631 filed an action for injunction with damages docketed as Civil Case No. 1312-A of the same Regional Trial Court, against private respondents (1) Adora Cruz, (2) Antonio Cruz, and (3) Ruben Gongora, and (4) Eduardo Cruz, (5) Concepcion Cruz, (6) Teresita Cruz, (7) Mario Jose, (8) Mariano Gongora, (9) Hector Jose, (10) Pio Z. Martinez, (11) Juan S.P. Herras, and (12) the Honorable Dominador Domingo (See Decision of Court of Appeals in CA-G.R. SP No. 16527, p. 33, Rollo).

On December 6, 1988, the trial court in Civil Case No. 1311-A issued a restraining order directing herein private respondents and the other defendants in said case to refrain from implementing the alias writ of demolition.

Private respondents Adora Cruz, et al. filed a petition for certiorari and prohibition with the Court of Appeals docketed therein as CA-G.R. SP No. 16527, praying that the order dated December 6, 1988 issued in Civil Case No. 1311-A be annulled and that the Honorable Patricio Patajo, the Presiding Judge of the Regional Trial Court of Antipolo, Rizal, be prohibited from conducting further proceedings in Civil Cases No. 1243 and No. 1311. This was the third time the case was brought before the Court of Appeals.

On August 30, 1990, the Court of Appeals rendered its decision in SP No. 16527 declaring the order dated December 6, 1988 null and void. On September 25, 1990, the Court of Appeals denied herein petitioners' motion for reconsideration.

Hence, the instant petition upon the following grounds:

(a)     The case of Suson vs. Court of Appeals, 172 SCRA 70, 75, does not apply in this case. (p. 11, Rollo)

(b)     Petitioners are lawful occupants of the portions of the parcel of land decreed by the Bureau of Lands as alienable public domain. They cannot be deprived of their possessory rights without due process of law. (p. 14, Rollo)

(c)     Respondents' cause of action in the ejectment cases is anchored on ownership of said parcel of land. Now that the Bureau of Lands has decreed said parcel of land as alienable public in nature, respondents are not entitled to the relief of possession. (p. 15, Rollo)

(d)     The alias writ of demolition has varied the terms of the decision in the ejectment cases and is, therefore, null and void. (p. 16, Rollo)

The grounds propounded by petitioners may be condensed to one issue, namely, whether the writ of execution issued in Civil Cases No. 630 and No. 631 may be enforced against petitioners.

It is to be stressed that petitioners have not been impleaded as party defendants in Civil Cases No. 630 and 631 although they are occupying portions of the parcel of land, subject-matter of said cases. The rule is that a judgment can not bind persons who are not parties to the action (Vda. de Sengbengco vs. Arellano, 1 SCRA 711 [1961]; Hollero vs. Court of Appeals, 11 SCRA 310 [1964]; Plata vs. Yatco, 12 SCRA 718 [1964]). This rule is anchored on the constitutional right of a person to due process of law. No person shall be condemned or judgment rendered against him without due process of law. Thus, this Court in Macabingkil vs. Yatco, 21 SCRA 150 [1967]) held:

As far back as 1908, U.S. v. Ling Su Fan, this Court affixed the imprimatur of its approval on Webster's definition of procedural due process. Thus: "By the law of the land is more clearly intended the general law, a law which hears before it condemns, which proceeds upon inquiry and renders judgment only after trial." This court in a 1924 decision, Lopez v. Director of Lands, after quoting the above added that due process "contemplates notice and opportunity to be heard before judgment is rendered, affecting one's person or property." It is satisfied according to another leading decision: "If the following conditions are present, namely: (1) There must be a court or tribunal clothed with judical power to hear and determine the matter before it; (2) jurisdiction must be lawfully acquired over the person of the defendant or over the property which is the subject of the proceeding; (3) the defendant must be given an opportunity to be heard; and (4) judgment must be rendered upon lawful hearing." (at p. 157.)

It is clear that petitioners were denied due process of law. They are possessors of portions of the parcel of land in question yet they were not impleaded as defendants in Civil Cases No. 630 and 631 for which reason any judgment rendered in said cases and any order or writ issued therein cannot be enforced against them.

It must be noted that respondent was not a party to any of the 12 ejectment cases wherein the writs of demolition had been issued; she did not make her appearance in and during the pendency of these ejectment cases. Respondent only went to court to protect her property from demolition after the judgment in the ejectment cases had become final and executory. Hence, with respect to the judgment in said ejectment cases, respondent remains a third person to such judgment, which does not bind her; nor can its writ of execution be enforced against her since she was not afforded her day in court in said ejectment cases.

The vital legal point here is that respondent did not derive her right or interest from the defendants-tenants nor from the plaintiff-landlord (the herein petitioner) but from the Bureau of Lands from which she had leased the property. She is neither a party nor successor in interest to any of the litigants in the ejectment cases.

We also find no merit in the contention of the petitioner that respondent having been duly heard by the Court, she was not deprived of her day in court and was accorded the due process of law.

It cannot be said that the constitutional requirements of due process were sufficiently complied with because the respondent had been duly heard. Indeed, respondent was heard but simply hearing her did not fulfill the basic conditions of procedural due process in courts. When respondent appeared before the court to protect and preserve her property, the Court had not lawfully acquired jurisdiction over the property of the respondent because the premises of the respondent was not included in the ejectment cases and the judgment in said cases could not affect her property, much less demolish the same. In the leading case of El Banco-Espanol-Filipino v. Palanca cited in Macabingkil v. Yatco, et al., We laid down the court's constitutional requirements of due process, thus -

"As applied to judicial proceedings. . . it may be laid down with certainty that the requirements of due process [are] satisfied if the following conditions are present namely: (1) There must be a court or tribunal clothed with judicial power to hear and determine the matter before it; (2) jurisdiction must be lawfully acquired over the person of the defendant or over the property which is the subject of the proceedings; (3) the defendant must be given an opportunity to be heard; and (4) judgment must be rendered upon lawful hearing."

Respondent pursued various steps to protect her property from the invasion and encroachment of the petitioner, abetted by her counsel and the deputy sheriff. She filed a motion for contempt; she protested to the Sheriff of Manila; she appealed to the Director of the Bureau of Lands; she filed an urgent motion to suspend the writ of demolition. Although the motions for contempt and for suspension were heard by the court, such actions taken after the judgment had become final and executory did not make the respondent a party litigant in the ejectment cases. The respondent remained a stranger to the case and she cannot be bound by the judgment rendered therein, nor by the writs of execution and demolition issued in pursuance to said judgment. Intervening as a prejudiced owner of improvements being wrongly demolished merely to oppose such order of demolition, upon learning that the said order was directed against premises not her own, is not the same as being a party to the suit to the extent of being bound by the judgment in the case where such order of demolition was issued. Furthermore, it must be noted that said petitions were filed after the promulgation of the decision in the ejectment cases and while in the process of execution. It is not proper to speak of an intervention in a case already terminated by final judgment. (Lorenzana vs. Cayetano, 78 SCRA 485, [1977] at pp. 490­-492).

The constitutional requirements of due process as set forth in the leading case of El Banco-Espanol-Filipino, v. Palanca, (37 Phil. 934 [1918]), reiterated in Macabingkil v. Yatco, supra, and again in Lorenzana vs. Cayetano, supra, are for convenience once more quoted:

As applied to judicial proceedings ... it may be laid down with certainty that the requirements of due process [are] satisfied if the following conditions are present namely: (1) There must be a court or tribunal clothed with judicial power to hear and determine the matter before it; (2) jurisdiction must be lawfully acquired over the person of the defendant or over the property which is the subject of the proceedings; (3) the defendant must be given an opportunity to be heard; and (4) judgment must be rendered upon lawful hearing."

Clearly, the second requirement afore-mentioned does not obtain in Civil Cases No. 630 and 631, for the trial court in said cases did not acquire jurisdiction over the persons of petitioners as they were not impleaded therein and were consequently not summoned to appear and present their defenses to resist the claims of private respondents.

The fact that petitioners filed, as afore-mentioned, an opposition to the issuance of a writ of demolition in Civil Cases No. 630 and No. 631 does not signify that they had voluntarily submitted themselves to the jurisdiction of the trial court, precisely because the very purpose of said opposition is that no writ of demolition should be issued or enforced against them as they are not parties to said case. Furthermore, it cannot be said that they had intervened in said cases by the filing of the afore-mentioned opposition for the reason that there can be no intervention in a case already terminated by final judgment (Lorenzana vs. Cayetano, supra, p. 492).

The right to due process is one of the building blocks of the edifice of our democratic form of government, and courts must ever be vigilant in safeguarding it, otherwise persons might be dragooned to jail without so much as the filing of a complaint, or they may one morning wake up with all their hard-earned property suddenly gone without so much they being aware of the cause therefor.

WHEREFORE, the petition is GRANTED. The assailed decision dated August 30, 1990 of respondent Court of Appeals is hereby ANNULLED and SET ASIDE and the writs of execution and demolition in Civil Cases No. 630 and 631 are hereby declared null and void and unenforceable in so far as petitioners are concerned.

SO ORDERED.

Feliciano, (Chairman), Bidin, Davide, Jr., and Romero, JJ., concur.