How do Catholics understand how the title “Lord” for Jesus is dependent on his resurrection at Ro 14:9 if it means he is God?

Catholics appear to teach that after Pentecost Christians understood that calling Jesus Lord was the same as calling him God.

This is true. The article you quoted described how "psychologically" speaking the apostles became convinced that Jesus is God only after:

• Resurrection: "the proof" promised by the sign of Jonah given by Jesus prior to His death; that's how Thomas became convinced when he put his fingers into the mark of the nails, and
• Pentecost: which resulted in the emboldening of the apostles by the Holy Spirit.

This is all straightforward and understandable. No argument here.

But then you bring up Rom 14:9:

How do Catholics understand how the title “Lord” for Jesus is dependent on his resurrection at Ro 14:9 if it means he is God?

How does being revived (lived again, ASV) make him Lord of both the dead and the living?

The premise of your question is that Jesus obtained the title "Lord" only after his death and resurrection, and that Paul implied this in Rom 14:9. Is this true?

I don't think so, for at least 2 reasons:

• First, to the apostles, death and resurrection was NOT the only basis for calling Jesus "Lord", thus equating Him with the God of the Old Testament. Death and resurrection is only part of the whole reasoning (out of scope in this question).

• Second, Paul's use of "Lord" in Rom 14:9 phrase "to be Lord both of the living and of the dead" is simply to emphasize Christ's sovereignty (lordship) over all people, whether they are living or dead. The use of the word "Lord" in Rom 14:9 is different than in the preceding verse Rom 14:8. In Rom 14:8 Paul used "Lord" to refer to Jesus. The NLT translation of Rom 14:6-9 should make the two usages and the context clear:

  ⁶Those who worship the Lord on a special day do it to honor him. Those who eat any kind of food do so to honor the Lord, since they give thanks to God before eating. And those who refuse to eat certain foods also want to please the Lord and give thanks to God. ⁷For we don’t live for ourselves or die for ourselves. ⁸If we live, it’s to honor the Lord. And if we die, it’s to honor the Lord. So whether we live or die, we belong to the Lord. ⁹Christ died and rose again for this very purpose -- to be Lord both of the living and of the dead.

Thus the context of Rom 14:9 is not to establish the un-Christian doctrine that only after Jesus was resurrected that Jesus obtained the title "Lord". The apostles understood Jesus to already be of the same essence as the OT God since birth, although they "psychologically" realized this retroactively. Paul took it as a given, part of the tradition he already received before AD 57, the approximate year when the letter was written. AD 57 was more than 2 decades after Pentecost, so by that time the apostles were already used to call Jesus as "Lord" with conviction.

To qualify this answer as a Catholic answer, I appeal to St. Paul's understanding of his own letter, properly interpreted by us. I believe every Trinitarian denomination would interpret Rom 14:7-9 similarly when it comes to Jesus's title as Lord. I invite the Catholic members of the C.SE community to refute this interpretation if it is in conflict with official Roman Catholic teaching.

Fr. Cornelius à Lapide, S.J., notes that Romans 14:9 corroborates the previous verse ("For whether we live, we live unto the Lord; or whether we die, we die unto the Lord. Therefore, whether we live, or whether we die, we are the Lord's.").

He also notes that Romans 14:9 does not say

"so that He may become Lord,"
_{ut fiat Dominus}

as though He did not before then have "the right and power of ruling" (jus et potestatem dominandi), but

"so that He may rule,"
_{ut…dominetur [=κυριεύση]}

i.e., "exercise His received power and rule" (exerceat acceptæ potestatis et dominii usum).

For Christ, from the first instant of His incarnation, by reason of the hypostatic union, was Lord of all: but after His death He received the full exercise of this rule. Similarly, Christ, by suffering and dying, merited judicial power, and also bodily glory; although it is owed to Him by reason of the hypostatic union, He also obtained it after the resurrection by the merit of His humility and death. Additionally, remember the Apostle here regarding the resurrection of Christ; because this exemplar is of our resurrection. [cf. Rom. 6:4-5] For as Christ died that He may rule the dead, so He resurrected that He may rule the living: therefore, let us arise unto life everlasting, that Christ may rule us living forever.

^{Nam Christus a primo instanti suæ incarnationis, ratione unionis hypostaticæ, fuit Dominus omnium: sed post mortem hujus dominii plenum exercitium accepit. Pari modo Christus potestatem judiciariam, æque ac corporis gloriam, licet ratione unionis hypostaticæ sibi debitam, patiendo et moriendo meruit, eamque merito suæ humilitatis et mortis adeptus est post resurrectionem. Adde, meminisse Apostolum hic resurrectionis Christi; quia hæc exemplar est nostræ resurrectionis. Sicut enim Christus mortuus est ut dominetur mortuorum, ita resurrexit ut dominetur vivorum: ergo resurgemus in vitam æternam, ut Christus nobis vivis dominetur in æternum.}

St. Thomas Aquinas succinctly summarizes this in his commentary on Romans 14:9:

1104. Second, he [St. Paul] assigns the cause of this condition, saying: for to this end Christ died and rose again, i.e., by his death and resurrection he obtained the right to be lord of the living, because he rose to begin a new and perpetual life, and of the dead, because by dying he destroyed our death: he died for all that those who live might live no longer for themselves, but for him who for their sake died and arose (2 Cor 5:15).

^{1104. Secundo assignat causam huius conditionis, dicens in hoc enim Christus mortuus est, et resurrexit, id est hoc adeptus est sua morte et resurrectione, ut vivorum dominaretur, quia resurrexit, vitam novam et perpetuam inchoando, et mortuorum, quia mortem nostram moriendo destruxit. II Cor. c. V, 15: pro quibus mortuus est Christus, ut qui vivunt, iam non sibi vivant, sed ei qui pro eis mortuus est, et resurrexit.}

The argument that calling Jesus "Lord" necessarily or always refers to his divinity, I suspect, is a novel one; and non-magisterial catechetical resources carry no guarantee of the soundness of their argumentation for doctrine, since the deposit of faith was handed on largely without explanation of the doctrines, containing only the doctrines themselves: various explanations and arguments for said doctrines' validity accumulating over time. That said, there are certain instances which make it clear that for early Christians, the lordship of the Messiah, and his divinity, were without scruple conflated and mingled into one conception of one single person, one divine Messiah - inasmuch as that's precisely who Jesus is in the New Testament: "God .. made flesh." (John 1). One key example is, "My Lord and my God!" (John 20:28). Or the instances of "The Day of the Lord" being conflated with the "Day of Christ." Yahweh the only Saviour with Jesus the Saviour of all. Etc. Clearly "Lord" with reference to Jesus is directly calling Him God, as in the Lord of all.

Consider two chapters prior:

Romans 10:9-13 (DRB) For if thou confess with thy mouth [that Jesus is Lord], and believe in thy heart that God hath raised him up from the dead, thou shalt be saved. 10 For, with the heart, we believe unto [righteousness]; but, with the mouth, confession is made unto salvation. 11 For the scripture saith: Whosoever believeth in him, shall not be confounded. 12 For there is no distinction of the Jew and the Greek: for the same is Lord over all, rich unto all that call upon him. 13 For whosoever shall call upon the name of the Lord, shall be saved.

St. Paul quotes Joel 2:32 here:

And it shall come to pass, that every one that shall call upon the name of the Lord [Yahweh] shall be saved: for in mount Sion, and in Jerusalem shall be salvation, as the Lord hath said, and in the residue whom the Lord shall call.

Thus, Romans 14:9 might rightly be understood in the sense that God in some sense can become 'more' the Lord of the living and the dead by partaking of life and death in the humanity of Christ, than if He hadn't - and only in that sense. Analogous to how Hebrews 4:15 describes the incarnation (Phil. 2):

For we have not a high priest, who can not have compassion on our infirmities: but one tempted in all things like as we are, without sin.

On the one hand, not having compassion on our infirmities wouldn't follow from not being human, since God can make Christ quite capable of sympathizing with those who were, according to Hebrews 1, and John 1, were created through him, and which all consist in him (Col. 1:17).

Hebrews 2:17-18 (DRB) Wherefore it behoved him in all things to be made like unto his brethren, that he might become a merciful and faithful high priest before God, that he might be a propitiation for the sins of the people. 18 For in that, wherein he himself hath suffered and been tempted, he is able to succour them also that are tempted.

As if Christ, who is greater than the angels, couldn't do what angels an do. Thus the argument is that it is fitting and a way in which He can in yet another way be considered the perfect mediator, not that if He lacked humanity, He couldn't save another way, for example.

As with Romans, the author of Hebrews has already called Him God:

Hebrews 3:1-4 (DRB) Wherefore, holy brethren, partakers of the heavenly vocation, consider the apostle and high priest of our confession, Jesus: 2 Who is faithful to him that made him, as was also Moses in all his house. 3 For this man was counted worthy of greater glory than Moses, by so much as he that hath built the house, hath greater honour than the house. 4 For every house is built by some man: but he that created all things, is God.

There is as much difference between God and some man as there is between Christ and Moses. Why? Because He is God in the flesh. A man, yes, but who is that man? Son of Mary, or Son of God first, "from ancient times, even from the days of eternity?" The latter.

The word translated "[that] he might be lord of both" is a single verb in the Greek (κυριευση), meaning, "he might be lord." This never refers to being a particular lord or the Lord, but to *the quality of having or exercising governance over*, or exercising one's lordship over someone or something. It doesn't refer to becoming Lord.

However, here, even with the Catholic or trinitarian conception of Jesus, this clearly refers to the humanity of Christ ("he died and rose" etc.) and not to his divinity, in which He is already Lord by virtue of His being God. Here, Christ becomes the lord of the living and the dead by buying them from sin, and being "the Saviour of all men" (1 Tim. 4:10).

St. Paul's point in most or all of these instances is that Jesus is Lord in every way imaginable - as both God and as man. King and Lord in the sense of the new Adam and Messiah as well as in the sense of God.