Musar su Salmi 136:3

I believe that Rabbeinu Bachyah has provided the most plausible reason for the spelling with the vowel kametz. He states that the purpose of the kametz is to demonstrate that G–d is self- sufficient, and that therefore no possessive form can be used concerning Him. His words are truly inspired. There is another allusion in that vowel, however, namely that the vowel kametz is really a combination of the two vowels patach and chirik. If one were to use only the vowel chirik, the word would apply to human beings, whereas if one were to use only the vowel patach, it would apply to all three men, i.e. it would be a plural, meaning "you (all) are my lords." The vowel kametz then is a combination of the singular and the plural. Abraham's intention then was to say: "Even though there may be many 'lords,' You O G–d are my only true Lord, the Lord of Lords." Psalms 136,3 also speaks of אדוני האדונים, "the Lord of Lords."