The answer
The answer is the same for each question. In each case, we are speaking to the person (not about the person), which means we are speaking in the "second person," that is, "You were," "You who dwell," "You who have." Since we are addressing the father or son directly, we must use the second person form of the verb. The reason why it seems unusual is because we are not saying "You" immediately in front of the verb. In speaking to the Son, we would say, "You were born of a virgin." But in speaking about Him (third person), we would say, "He was born of a virgin." Also, in normal conversation, we wouldn't say to another, "You who were born …," as this is too formal, although grammatically correct. We might say, "You are the one who was born …," but here we have switched to the third person.When we take a look at the Greek construction, since the Trisagion is all in Greek. In all three instances between "Holy Immortal" and "have mercy upon us" is a participial phrase, which is neither second nor third person, but an explanatory description of the One to whom we are praying. Trouble is, English forces us to make a choice: either "You who were born" or "You are the One who was born," in short, "who were."
Also the following from Holy Book of Joel 3:17.
So you shall know that I am the LORD your God, who dwell in Zion, my holy mountain. This is the same issue that you wrote about concerning the Divine Liturgy. Notice that it says "who dwell" (first person) not "who dwells" (second person), because God Himself is speaking. As we know, in English it is I who dwell, You who dwell, God who dwells.In the Holy Book of Joel 3:17, since "God" is right before "who dwell" - and because there are several words between "I" and "dwell" -- the ear can easily think it should be "dwells." The same thing happens in the Liturgy.
I checked the Holy Book of Joel 3:17 in Hebrew and Greek, and in both cases "dwell" is a participle ("dwelling"), the same construction we find in the Trisagion.
A participle doesn't sound quite right in English, though:
So you shall know that I am the LORD your God dwelling in Zion, my holy mountain.That's why translators use "who" in these cases.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)