«There are two general venues within patristic and early Christian literature in which Exodus 3:14 appears. The first and less frequent consists of treatises aimed at matters ecclesial, catechal, liturgical, moral or of spiritual formation. These texts, when speaking of Moses and the burning bush generally do not pause at the formula of 3:14a, but rather emphasize the call of Moses and through some means make a connection between the God of Moses and the God of the Christians. The second venue consists of treatises dealing exclusively with theological controversy, and it is here that Exodus 3:14 appears consistently. More specifically, Exodus 3:14 is employed by Christian writers first in the controversies against the Jews, in which it is used to affirm the Son's divinity; second, in the apologies addressed to the Greeks, where it is used in definitions of True God contra the idols of pagans, as well as in attempts to demonstrate the dependence of Plato's concept of "Being" upon Moses; third, and most notably through Eusebius of Caesarea, in all matters pertaining to the relations of the Trinity, especially contra Sabbellianism and Arianism. Thus by the Council of Nicea (325 AD), Jesus will have been thoroughly identified with the "angel" of Exodus 3:2 and orthodoxy will require that 3:14a (Greek: ego eimi o oon) be applied as much to the Son as to the Father, since they are homoousioi.
During these controversies the following theo-grammatical implications become almost universally adopted in treatments of 3:14. The use of the present participle (oon) is seen as an indication of God's eternity. The verb "to be" (eimi) will be used in an absolute manner such that only one Being can be described as such, while all other creatures possess "being" only in so far as they relate to o oon. The root common to o oon (LXX 3:14) and ousia allows reading this title back to the divine essence (ousia).
The scene of the burning bush is used very early on by Christian authors as evidenced by the writings of Justin Martyr (d. 165 AD), who equates Jesus not only with the "angel" of 3:2 but also "Lord" (Hebrew: YHWH; LXX: Kurios) in 3:4ff. Justin's theology views the Father as eternally unnameable (anoomastos) and through Exodus 3:14 (and other OT theophanies) views Jesus as the God who appeared to the patriarchs. "God's angel spoke to Moses in a flame of fire coming out of the bush saying: I am the One who is, God of Abraham, God of Isaac, and God of Jacob". Justin elsewhere argues that the angel of 3:2 is the divine Logos of John 1:1, whom the Christians call "the Lord Jesus Christ". Thus Jesus becomes not only the YHWH of Exodus 3, but the God of the patriarchal period, a status which is seen as clearly attesting to the Son's divinity.
Irenaeus also assigns to the Son the words spoken to Moses in 3:14. It is the Son who descends to rescue the Israelites "For it is the Son who descended and ascended for the salvation of men. Thus through the Son who is in the Father and has the Father in himself, He who is (o oon) has been revealed." For Irenaeus the title o oon signifies that the Lord of the Christians is the only true God, being par excellence as opposed to false gods "who have no being". Throughout his use of Exodus 3:14 Irenaeus continues the practice noticed in Justin of not distinguishing between the "angel" of 3:2 and YHWH/Kurios of 3:4ff. This becomes characteristic of subsequent Christian writers as well, and significantly distinguishes these writings from their Jewish counterparts. Whereas Jewish treatments clearly see 3:14 as a declaration of a name uniquely held by God, early Christian treatments clearly understand the name to be common to both Father and Son. However, already in Justin we see an appeal to the "unnameable" Father. This strand will be increasingly developed by later Christian writers. In essence, the Father is increasingly viewed as static Being par excellence and thus beyond categorization while the Son is identified with any divine activity or vocalization in the Old Testament.
Exodus 3:14 also figured heavily throughout the fourth century AD in controversies involving the trinitarian doctrine set forth at the Council of Nicea. First the Subordinationists, then the Arians, and finally the Eumonians, invoked the Jewish reading of Exodus 3:1-5 which clearly distinguishes between the "angel" of 3:2 and YHWH of 3:4ff. Appeal to the traditional Jewish reading and the distinction it involved allowed these groups to argue that the title o oon and all the significations the title was now pregnant with should not be assigned to the Son. In contrast, the proponents of Nicea were then all the more obliged to argue the validity of applying Exodus 3:14 to Jesus. The primary documentation for the dialogues taking place within the Nicean Council come from Eusebius of Caesarea, who himself was a significant contributor to the proceedings.
Also present at the Council was Athanasius who uses the title o oon of 3:14 as a scriptural proof for the defense of the otherwise non-biblical term ousia, a central term in the Nicean formula. Athana[s]ius argues that since God defined himself by the word oon, one may speak of his ousia. This in turn allows one to say that the Son "proceeds from the ousia of the Father" as much as one may say simply "proceeds from God". Thus for Athanasius the title o oon of 3:14 is not treated as a unique title for God, but rather as an argument for the Nicean formula of the Son's generation, his "proceeding from the divine ousia".»
«Exodus 3:14 and the Divine Name: Textual and Historical Considerations»
[«Το Έξοδος 3:14 και το Θεϊκό Όνομα: Κειμενική και Ιστορική Εξέταση»],
Quodlibet Journal Vol./Τόμ. 4 No./Αρ. 4, November/Νοέμβριος 2002.