Kyrios: Lord or YHWH?

What is this concept?

Kyrios (Greek: kyrios, κύριος, "lord, master, sir") is the single most common title applied to Jesus in the New Testament. It appears hundreds of times across the epistles, the Gospels, and Acts. And yet its meaning is remarkably slippery, because the same Greek word covers an enormous range — from a polite form of address all the way up to a substitute for the personal name of Israel's God.

Understanding kyrios is not optional for this debate. When Paul writes "Jesus is Lord," does he mean Jesus is YHWH? Or that Jesus is the supreme human agent YHWH has appointed? The answer you give here shapes almost everything else.

Where does it come from?

In everyday Greek, kyrios was simply a word for someone with authority. A slaveholder was kyrios to the enslaved. A husband could be kyrios to his wife. A king was kyrios to his subjects. In the Roman imperial cult, Caesar was acclaimed as kyrios — "lord" — a political title asserting supreme earthly authority.

But something much more consequential happened in the Jewish Greek scriptures. When the Hebrew Bible was translated into Greek (the Septuagint, or LXX), the translators needed a way to render the divine name YHWH, which Jews had stopped pronouncing aloud. They chose kyrios. Roughly 6,700 times, the LXX replaces the personal, covenant name of Israel's God with this single Greek word.

At the same time, the LXX also uses kyrios to translate the Hebrew adon and adoni (אדון / אדני, "lord, master") — words used for human superiors, kings, and masters. The result is that the Greek reader of the LXX encounters the same word, kyrios, for both God and for human lords. The Hebrew distinction between the divine name and a human title is flattened.

This ambiguity is not a minor footnote. It is the engine that drives much of the Christological debate.

How does it appear in the New Testament?

The New Testament uses kyrios for Jesus across the full spectrum of meaning:

Polite address ("sir"): The Samaritan woman at the well calls Jesus kyrie before she has any idea who he is (John 4:11). She is simply being polite to a stranger. Blind Bartimaeus uses it when asking for help (Mark 10:51). In these cases, no one is making a theological claim.

Master or owner: In parables, the "lord of the vineyard" (Matt 20:8) and the master who entrusts talents to servants are called kyrios. Throughout the New Testament, slaveholders are called kyrios by those they enslaved. This is authority language — real authority — but human authority.

Ruler: Roman imperial usage applied kyrios to Caesar. When early Christians confessed "Jesus is kyrios," part of the force was political: Jesus, not Caesar, holds supreme authority.

God (YHWH): And here the stakes rise sharply. Several New Testament passages take Old Testament texts that originally referred to YHWH and apply them to Jesus. These are the texts that make the debate so intense.

"God highly exalted him and gave him the name that is above every name, so that at the name of Jesus every knee should bow... and every tongue confess that Jesus Christ is Lord, to the glory of God the Father."

— Philippians 2:9-11, quoting Isaiah 45:23

Isaiah 45:23 is a fiercely exclusive YHWH text. In its original context, YHWH declares that he alone is God, and every knee will bow to him. Paul takes this language and applies it to Jesus. Similarly, Romans 10:9-13 quotes Joel 2:32 — "everyone who calls on the name of YHWH will be saved" — and applies it to calling on the name of Jesus. And 1 Corinthians 12:3 says plainly: "No one can say 'Jesus is Lord' except by the Holy Spirit."

These are not casual uses. Something significant is happening when YHWH-texts are redirected to Jesus. The question is what.

Why does it matter for the debate?

The case from Philippians 2 is powerful, and every serious reader should feel its force. Isaiah 45:23 is not a generic text about lordship — it is YHWH claiming exclusive, unshared sovereignty. When Paul applies this language to Jesus, he is doing something no first-century Jew would do lightly.

But the same passage contains a detail that pulls in the other direction. Philippians 2:9 says God gave Jesus the name above every name. The exaltation is a gift, not an inherent possession. And the purpose of every tongue confessing Jesus as Lord? "To the glory of God the Father." The glory flows upward. Jesus is Lord, but the Father remains the ultimate recipient of worship. This is exactly the pattern that agency theology would predict: God exalts his supreme agent and confers his own name upon him, so that honouring the agent honours the sender.

And then there is Psalm 110:1 — arguably the most important and most underappreciated Old Testament text for the entire Christological debate.

"The LORD [YHWH] said to my lord [adoni]: 'Sit at my right hand, until I make your enemies your footstool.'"

— Psalm 110:1

This is the most frequently quoted Old Testament verse in the entire New Testament. Jesus cites it about himself (Mark 12:36-37). Peter builds his Pentecost sermon around it (Acts 2:34-36). The author of Hebrews returns to it repeatedly. It is everywhere.

And the Hebrew is unambiguous. Two different words appear: YHWH (the divine name) speaks to adoni (אדני, "my lord"). These are not the same. YHWH is God. Adoni is the one YHWH addresses — and adoni is explicitly distinguished from YHWH by the grammar of the sentence itself.

This creates a genuine tension. On one hand, YHWH-texts like Isaiah 45:23 are applied to Jesus. On the other, the single most-quoted OT text in the NT explicitly identifies the Messiah as adoni — a human lord whom YHWH exalts — not as YHWH himself. If the NT authors understood Jesus as the fulfilment of Psalm 110:1, they understood him as the human lord whom YHWH seats at his right hand. Both threads run through the New Testament simultaneously, and any honest reading must reckon with both.

What do the different traditions say?

Trinitarian: The application of YHWH-texts to Jesus is not merely agency language — it signals Jesus's inclusion within the divine identity. No mere agent could receive what Isaiah 45 reserves exclusively for YHWH. The pattern across Paul, Hebrews, and Revelation is consistent: Jesus shares in the unique prerogatives of God. Psalm 110:1 does not undermine this, because the "two lords" pattern reflects the inner-Trinitarian relationship, not a division between God and a creature. Scholars such as Richard Bauckham, Gordon Fee, and David Capes have developed this argument in detail.

Biblical Unitarian: Kyrios applied to Jesus carries the adoni sense — lord, master, king — not the YHWH sense. The OT quotations describe God acting through his exalted human agent and conferring his own name upon that agent, exactly as Psalm 110:1 predicts. The fact that Philippians 2:11 says the confession is "to the glory of God the Father" confirms the agency pattern: Jesus is supreme lord under God, not God himself. The adoni/adonai distinction in Psalm 110:1 is the interpretive key. Anthony Buzzard, Mark Graeser, and John A. Lynn have pressed this argument. Dale Tuggy ("Trinity," Stanford Encyclopedia of Philosophy) reinforces it from the angle of 1 Corinthians 8:6: "one Lord Jesus Christ" distinguishes the Lord from the one God (the Father). Kyrios here is a title of authority and agency conferred by the one God, not an identification with YHWH. Sean Finnegan (Restitutio, ep. 580) highlights Acts 2:36 — "God has made him both Lord and Christ" — where kyrios is explicitly a status conferred by God upon Jesus, not a pre-existing divine identity recognised after the fact. As BiblicalUnitarian.com documents, the Septuagint uses kyrios widely — for YHWH, but also for human masters, kings, and social superiors. Context, not the word itself, determines whether the term carries divine or human force.

Logos Christology: The pre-incarnate Logos bears the title kyrios in a way that exceeds what any ordinary human agent could claim, but without full co-equality with the Father. The Logos is genuinely divine — the first and greatest emanation of the one God — and so rightly receives the YHWH-texts as one who shares in divine nature by derivation. This position, found in Justin Martyr and explored by Larry Hurtado, occupies the middle ground: more than agency, less than co-equal identity.

Go Deeper

For further study on how kyrios functions in New Testament Christology:

• David Capes, Old Testament Yahweh Texts in Paul's Christology
• Richard Bauckham, Jesus and the God of Israel
• Anthony Buzzard, The Doctrine of the Trinity: Christianity's Self-Inflicted Wound
• Larry Hurtado, Lord Jesus Christ: Devotion to Jesus in Earliest Christianity
• Dale Tuggy, "Trinity" in Stanford Encyclopedia of Philosophy
• Sean Finnegan, Restitutio, ep. 580: "An Honest Evaluation"
• BiblicalUnitarian.com — encyclopaedic resource on kyrios and NT titles

See also the passage analyses for Philippians 2:5-11, 1 Corinthians 8:6, and Acts 2:22-36.