The word Tzevaot (צבאות, [tsvaot]) appears in the OT in reference to armies or hosts. We read, for instance, in Exodus (Douay-Rheims translation):
And he will not hear you: and I will lay my hand upon Egypt, and will bring forth my army (צִבְאֹתַי), and my people the children of Israel out of the land of Egypt, by very great judgments (7:4).
Which being expired, the same day all the army (צִבְאוֹת) of the Lord went forth out of the land of Egypt (12:41).
The same passages in the Septuagint read:
Kαὶ οὐκ εἰσακούσεται ὑμῶν Φαραώ· καὶ ἐπιβαλῶ τὴν χεῖρά μου ἐπ᾿ Αἴγυπτον καὶ ἐξάξω σὺν δυνάμει μου τὸν λαόν μου τοὺς υἱοὺς ᾿Ισραὴλ ἐκ γῆς Αἰγύπτου σὺν ἐκδικήσει μεγάλῃ (7:4).
Kαὶ ἐγένετο μετὰ τὰ τετρακόσια τριάκοντα ἔτη, ἐξῆλθε πᾶσα ἡ δύναμις Κυρίου ἐκ γῆς Αἰγύπτου νυκτός (12:41).
The word Tzevaot was redendered here as
dynamis (δύναμις) which has the general meaning of power, might or strength but can also mean a force of war which is closer to the meaning of the original Hebrew. In the Vulgate, Tzevaot is plainly rendered as
exercitus which is army:
Et non audiet vos : immittamque manum meam super Ægyptum, et educam exercitum et populum meum filios Israël de terra Ægypti per judicia maxima (7:4).
Quibus expletis, eadem die egressus est omnis exercitus Domini de terra Ægypti (12:41)
However, the same word is not translated when used as a divine epithet in the Sanctus. We are all familiar with the term
the Lord God of Hosts being rendered as
Dominus Deus Sabaoth in Latin. We hear it at Mass prior to the Canon. In Isaiah, the prophet uses the epiteth YHWH Tzevaot and this is rendered as
Lord of hosts except in the Septuagint:
And they cried one to another, and said: Holy, holy, holy, the Lord God of hosts (צְבָאוֹת), all the earth is full of his glory (6:3).
καὶ ἐκέκραγεν ἕτερος πρὸς τὸν ἕτερον καὶ ἔλεγον· ἅγιος, ἅγιος, ἅγιος Κύριος σαβαώθ, πλήρης πᾶσα ἡ γῆ τῆς δόξης αὐτοῦ (6:3).
Et clamabant alter ad alterum, et dicebant : Sanctus, sanctus, sanctus Dominus, Deus exercituum (6:3).
I assume that Sabaoth persists in the Latin liturgy because the Septuagint preserved Tzevaot in this instance. What I don't know is why the Septuagint did it. Was it to signify the specificity of the divine title of God as Lord of the heavenly and earthly armies?
I'd appreciate your inputs.