The Greek phrase kyrios mou translates the Hebrew word adoni, a term never used for God in the Old Testament. This is the word used by David in Ps 110:1 for the second lord, who by Jewish-Christian tradition represent the Messiah. In order to get around this, some Trinitarians claim two exceptions in the Psalms—16:2 and 35:23—where Adonai is also translated as kyrios mou. But even though the phrase looks the same in Greek, what’s going on in each passage is actually different. The contexts, the Hebrew behind the Greek, and the function of the words are not parallel, which means adoni is not the same as Adonai.
In Psalm 110:1, the Hebrew shows a deliberate contrast between two different lords. On the one hand is Yahweh, the LORD God; on the other is David’s lord, adoni, a title never used for Adonai. Hence, “my lord” is not Yahweh, but a distinct figure whom God exalts to His right hand to rule as His royal/messianic human king and priest. The whole psalm functions as a messianic royal oracle, applied in the New Testament to the man Jesus as the exalted Son of God, the Messiah at God’s right hand.
In Psalm 16:2, however, kyrios mou is used very differently. It is a direct address to YHWH alone:
“I say to YHWH, ‘You are my Lord [kyrios mou]’” (Ps 16:2).
Here “my Lord” is simply a confession of exclusive devotion to God Himself, with no second party or contrast involved.
Likewise, in Psalm 35:23 (LXX) we read:
“Awake and attend to my judgment, my God and my Lord (kyrios mou), to my cause” (Ps 35:23).
In this verse, “my Lord” stands in parallel with “my God” and clearly refers to Yahweh alone as the divine defender. It is a direct plea to God, not a dialogue between God and another human, messianic figure.
So the key differences are:
Referent – In Psalms 16:2 and 35:23, “my Lord” used for God alone (direct address, confession, or plea). In Psalm 110:1, “my lord” is a distinct figure addressed by Yahweh, a royal/messianic human exalted by God.
Structure – Psalm 110:1 is a dialogue: YHWH speaks to David’s “lord,” highlighting hierarchy and appointment. Psalms 16 and 35 have no such contrast—“my Lord” is simply a possessive way of speaking to the one God.
Theological function – Psalm 110:1 is messianic and royal, a promise of enthronement and victory for David’s superior human “lord.” Psalms 16 and 35 use “my Lord” in the language of personal piety and devotion to Yahweh exclusively.
Same Greek phrase on the surface, but different Hebrew structure, and a very different point. Therefore, it is shortsighted and contrary to biblical grammar to say Adonai is the same as adoni in Hebrew.
