I just came across the following from a Trinitarian apologist on Psa 110:1 (LXX 109:1); the context is an attempt to support the (false) claim that, in this verse, there are two Yahwehs (in other words, Yahweh said to Yahweh, or Yahweh said to ADNY, with the second Lord being numerically identical to Yahweh--an attempt to support a plurality of divine persons in one God [if that sounds inconsistent, it is Trinitarianism, so such should be expected]). The article can be found here; a good refutation of some of the bogus arguments were made by By Jaco Van Zyl, "Psalm 110:1 and the Status of the Second Lord--Trinitarian Arguments Challenged," in An E-Journal from the Radical Reformation: A Testimony to Biblical Unitarianism, winter/spring 2012, pp. 51-60. While I disagree with Van Zyl’s (Socinian) Christology, he does offer a good refutation of Shamoun and White on the issue of the topic of Psa 110:1.
Appendix 3: The Anti-Trinitarians are wrong – Yahweh is Adoni
In the main article, we examined the claim that David, in Psalm 110:1, called his sovereign (whom the NT identifies as the Messiah Jesus) as Adoni, a term which anti-Trinitarians claim is never used of Yahweh. We addressed the assertion that this term is always used for human beings or angels and how this somehow proves that Jesus cannot be God.
Here, we are going to provide evidence that the Hebrew Bible does call Yahweh Adoni since there were a few individuals who were given the name Adonijah (Adoniyah):
Sons were born to David in Hebron: His firstborn was Amnon the son of Ahinoam of Jezreel; his second, Kileab the son of Abigail the widow of Nabal of Carmel; the third, Absalom the son of Maacah daughter of Talmai king of Geshur; the fourth, Adonijah the son of Haggith; the fifth, Shephatiah the son of Abital; and the sixth, Ithream the son of David's wife Eglah. These were born to David in Hebron. 2 Samuel 3:2-5; cf. 1 Kings 1-2; 1 Chronicles 3:2 (1-9)
"With them were certain Levites—Shemaiah, Nethaniah, Zebadiah, Asahel, Shemiramoth, Jehonathan, Adonijah, Tobijah and Tob-Adonijah—and the priests Elishama and Jehoram." 2 Chronicles 17:8
"The Levites …Adonijah, Bigvai, Adin," Nehemiah 10:9, 16
The reader may be wondering how the name Adonijah proves or shows that Yahweh is called Adoni in the Old Testament. When it is kept in mind that Adonijah is a theophorus name (theophoric onomastica – a name which contains specific elements of the name or describes certain characteristics or roles of the Deity worshiped by the individual in question), and that it means "My Lord is (Adoni) Yahweh" or "Yahweh is my Lord,"
'Adoniyah (Strong's H138)
Adonijah = "my lord is Jehovah"
1) fourth son of David and Solomon's rival for the throne
2) Levite sent by Jehoshaphat to teach the Law
3) a chief of the people who co-operated with Nehemiah
Gesenius’ Lexicon
("Jehovah is my Lord"), [Adonijah], … (Source)
The reader should then be able to see the relevance this particular name has in establishing the fact that Adoni is indeed used for the one true God of all. The assertions of the anti-Trinitarians are, therefore, without any merit since they are in error concerning Adoni never being used for Yahweh and are further grossly mistaken in assuming that Jesus is simply a human agent of God because of the fact that he is supposedly never called Adonai, but Adoni.
This may sound impressive, but in reality, it is a false comparison (also note the use of Strong's Concordance, an incredibly dated resource). The “i” in names suh as Adonijah is not first person possessive, like the “i” in Adoni (“my lord”); instead, it is copulative (“is”). The possessive is not part of the name proper, and is usually supplied in parenthesis, so Adonijah would mean “lord is Yahweh.” Take the example of Adoniram (Heb:אֲדֹנִירָם); here is how Ludwig Koehler and Walter Baumgartner in The Hebrew and Aramaic Lexicon of the Old Testament (Brill) defines the term (note the possessive in brackets):
166 אֲדֹנִירָם
אֲדֹנִירָם: n.m.; אָדוֹן + רום “)my( lord is exalted” )Noth 145f(; NPun. אדנראם, Arm. with לְ precative ) אדנלרםIngholt, Hama 117; BASOR 123:28(: supervisor of Solomon and Rehoboam 1K 46 528; = אֲדֹרָם 2S 2024 1K 1218, = הֲדֹרָם 2C 1018. †
All these names show is that Adon (Lord) is predicated of Yahweh, not adoni (my lord).