Annotation C, Whether this passage pertains to the Trinity (Genesis 18:3)

Annotatio C

”Lord, if I have found favor in thy sight.” — Genesis 18:3

Thomas Cajetan is gravely reprehended by Ambrose [Catharinus], Archbishop of Compsa, because he took away from the present chapter an excellent passage from which — according to the doctrine of the saints, and the very voice of the whole Church — the mystery of the Trinity is elicited:¹ namely, when Abraham in the valley of Mamre saw three, and adoring one said, “Lord, if I have found favor in thy sight,” [Cajetan] himself, changing the singular voice into the plural, translated and expounded it, “My lords, if I have found favor in your sight.” But it appears that Ambrose is — as the adage runs — seeking a knot in a bulrush, and deliberately hunting occasions for calumny: for Cajetan, by this change of number, in no way derogates from the Trinity of the divine [Persons]; nay rather he establishes [it]… — nay rather he established the unity of the Trinity: he shows that the name Adonai, which contains a number of multitude, is [here] to be referred to the number of unity. Thus you will say: “Although Adonai is of plural number, signifying ‘my Lords,’ yet that it is here used for the singular the pronoun ‘thy’ makes manifest.” Thus he [Cajetan]. Rabbi David [Kimhi] says that the name אֲדֹנָי Adonai, which is of plural number, whenever it is written with qametz [cameza], is attributed to God the Creator for the sake of honor and excellence.