Lord (YHWH)
• For a fuller treatment of this name, the sacred tetragrammation, see the word study "The Name of the Lord" (coming soon)
Lord ('Adôn)
• In many passages, especially in the Psalms, 'Adon means "Master" or "Lord" when applied to Deity.
• For example, if you look closely at Psalm 8, you will notice the capitalization, "O LORD, our Lord" means "O Jehovah [Yahweh] our Lord [Master]," In Psalm 136:3, we are told to "give thanks to the Lord of lords ['adone ha adonim]," As so often when Lord refers to God, the plural form is used (even the 'adone part is plural, which refers to one Person, God).
• When the personal suffix for "my" in Hebrew is put on adon, it is generally adoni (singluar) for men and 'Adonai (plural) for God. HOwever, in Psalm 110:1, the singular form is used. Perhaps this is to stress the dual nature of our Lord: He is both God and Man. As God He is David's Lord, but as Man He is David's Son. Also, if the ancient text had used a plural for "my Lord," it might have seemed to be a copyist's error, since it would have Deity speaking to Deity before the revelation of the three Persons of the Trinity had been clearly made to mankind. However, there are Old Testament verses that certainly demand plurality of Persons in the Godhead (e.g., Gen. 1:26; 11:7; Prov. 30:4; Zech. 12:10)
Lord ('Adön)
• We use lowercase letters in the English Bible when the word lord refers to a mortal man. We have laready noticed that David was called "lord." Other rulers so designated in the Old Testament include the PHaroah (Gen. 40:1) and Saul (1 Samual 16:16). Other important leaders called 'adon include Joseph (Gen 42:10), Eli the priest (1 Sam 1:15), David's commander Joab (2 Sam 11:9), and the prophet Elijah (1 Kin 18:7).
• The concept of human "lords" is easier for Britons than for Americans to relate to, since Britain still has lords and the House of Lords. Even ordinary people were called this title of respect, however: Abraham by Sarah (Gen 18:12) and by his servant Eliezer (Gen 24, many times). Ruth also called Boaz "my lord" ('adoni) in Ruth 2:13.

• Having trounced the critical scribes and Pharisees by successfully answering their hard questions, Jesus posed some Bible questions of His own. He asked, "What do you think about the Christ? Whose Son is He?" That was an easy one.
• When they correctly answered, "The Son of David," He asked a second, much harder question: "How then does David in the Spirit call Him 'Lord,' saying: "The LORD said to my Lord, "Sit at my right hand, till I make your enemies Your foot-stools" '? If David then calls Him 'Lord,' how is He his Son?"
• They were stumped, as we would be, if we didn't have the New Testament to enlighten us.
• This one short passage illustrates nicely the three meanings of lordship indicated by the three varieties of capitalization of the words in the tie to this word study. The KJV tradition (followed by many modern Bibles) is to use all capitals in the Old Testament when "LORD" represents the personal name of the one true God, Jehovah or Yahweh. The NKJV goes a step further and also does this in the New Testament (as in v.44), but only where it is a direct quotation from the Old Testament and the original Hebrew reads the sacred name of YHWH.
• The Lord to whom Jehovah was speaking is capitalized to indicate dignity and deity. Whoever is meant, He is David's Lord and Master, yet He is seen as separate from YHWH in some way. Also David himself is a lord, and as king, is so called in several passages. For example, the woman of Tekoa addressed him as "lord, O king" in 2 Samuel 14:9. These variations in the English text are not arbitrary, but represent differences in the Hebrew original.