There are twenty-three places in St. John’s Gospel where Christ uses the phrase ἐγὼ εἰμί (ego ei·mi), (St. Joh. 4:26; 6:20, 35, 41, 48, 51; 8:12, 18, 24, 28, 58; 10:7, 9, 11, 14, 25; 13:19; 14:6; 15:1, 5; 18:5, 6, 8.) many authors have claimed that some or all of these occurrences represent a self-appellation of the divine title in Exod. 3:14, which appears in the KJV as “I am that I am.”
In the Septuagint, the divine title at Exod. 3:14 appears as ἐγώ εἰμι ὁ ὤν (ego ei·mi ho on) which translates to “I am the being” or “I am the self-existent one,” and the shortened form of this divine title is simply ὁ ὤν which means “the being.” St. John of Patmos uses ὁ ὤν as a divine title for the Father and the Son. (Rev. 1:4, 8; 4:8; 5:6, 7; 11:17; 16:5)
The LXX of Isa. 43:10 uses ἐγώ εἰμι as a divine title, but in this place, it is the Father who speaks to the Son, and therefore, to identify the Son with the speaker of Isa. 43:10 would be to argue that Jesus is the Father. Sabellianism is the inevitable result of this futile argument. White identifies the Jesus Christ as the “Jehovah” who spoke the words of Isa. 43:10, but this is a suffering servant song. (The Forgotten Trinity, p. 98-100). In the suffering servant songs, upon the Christian interpretation, God is the Father who sends his “servant” and Son, the Messiah, to suffer for the sins of the world. (1Pet. 2:23-25; St. Joh. 3:16, 18; cf. Isa. 53:5, 6, 9, 12) In Isa. 43:10 God speaks to his Son, “you are my servant whom I have chosen,” therefore, by identifying Jesus as the speaker here, White is identifying the Son with the Father. (cf. St. Matt. 3:17; St. Mk. 1:11; St. Lk. 3:22)
“Finally, we should make mention of the passages where Jesus uses the words, ‘I am’, either absolutely, or with a predicate such as life, light, bread. It has been argued that these, and in particular, the absolute occurrences, represent an allusion to the divine name… Our review of the (ἐγώ εἰμι texts in John) indicated that nowhere is such a sense demanded and that in each case a less extraordinary explanation is more natural. This is not to deny that the author (or his tradition) may have modelled Jesus’ self-declaration on those of Yahweh in Isaiah, but, as there are, the primary meaning in John is that Jesus is all he claims to be, as 8:28f aptly illustrates. Alleged use of the divine name as a self-appellation by Jesus fails to convince.” (William Loader, The Christology of the Fourth Gospel: Structure and Issues (Berlin, Bern, New York, Paris, Wien: Peter Lang, 1992), pp. 166.)
The phrase is often used as a simple form of self-identification, which carries no divine significance whatsoever, hence the apostles, “Lord, is it I? (ἐγώ εἰμι, κύριε);” (St. Matt. 26:22.) a nameless blind man, “I am he (ἐγώ εἰμι);” (St. Joh. 9:9.) Peter, “Behold, I am he whom ye seek (ἰδοὺ ἐγώ εἰμι ὃν ζητεῖτε); (Acts 10:21.) St. Paul, “I am indeed a Jew (ἐγώ εἰμι ἀνὴρ Ἰουδαῖος),” (Acts 22:3.) “(τοιούτους ὁποῖος καὶ ἐγώ εἰμι);” (Acts 26:29.) and many Old Testament figures in the Septuagint, often with a predicate, but also without. (Gen. 23:4; 24:34; 30:2; 31:38, 41; 45:3, 4; Exod. 4:10; Deut. 31:2; Jdg. 6:16; 9:2; 16:17; 17:9; Ruth. 2:10; 3:9, 11; 4:4; 1Sam. 1:15; 4:16; 9:19; 17:43; 2Sam. 1:8, 13; 2:20.) The canonical Gospels sometimes treat the phrase “I am” (ἐγώ εἰμι) as a sort of euphemism which means ‘I am the Messiah,’ and this might be seen clearly in the Olivet Discourse,
St. Matt. 24:5
For many will come in My name, saying, ‘I am the Christ,’ and will deceive many.
St. Mark 13:6For many will come in My name, saying, ‘I am He,’ and will deceive many.
St. Luke 21:6
For many will come in My name, saying, ‘I am He.’
The phrase “I am the Christ” is substituted with “I am” (ἐγώ εἰμι) in the parallel accounts in St. Mark and St. Luke, the expressions are treated as equivalent. (There is no word for “he” in St. Mk. 13:6, the saying is simply “I am.”)
“Three other occurrences (8.24, 28; 13.19) are I believe correctly rendered by the NEB 'I am what I am," namely, the truth of what I really am. They do not carry with them the implication that he is Yahweh (indeed in the latter two especially there is contrast with the Father who sent him, but in Johannine terms, ‘the Christ, the Son of God'. Barrett is usually emphatic at this point. Referring to 8.28 he writes, 'It is simply intolerable that Jesus should be made to say "I am God, the supreme God of the Old Testament, and being God I do as I am told"''; and to 13.19, I am God and I am here because someone sent me.' The sole remaining instance is 8.58.' This certainly asserts pre-existence, as in the Baptist's statement of 1.15 and 30, but there, as we saw, the subject is specifically designated 'a man.' That Jesus is arrogating to himself the divine name is nowhere stated or implied in this Gospel. Even 'the Jews' do not accuse him of this - only of calling God 'his own Father.'" (John A. T. Robinson, The Priority of St. John (United States: Wipf and Stock Publishers, 1985), p. 386.)
The statement at John 8:58, if not a divine claim of itself, is certainly a claim to pre-existence. The final clauses, “before Abraham was, I am,” are part of a set of Greek expressions sometimes called past of present actions (PPA), and use present tense verbs to express continuous existence or a continuous action. (St. Joh. 5:6; 14:9; 15:27, 29; Rev. 21:1; Acts 27:33) Winer explained the category as follows, and even cited St. Joh. 8:58 as a specific example,
“Sometimes the Present includes also a past tense (Mdv. 108), viz. When the verb expresses a state which commenced at an earlier period but still continues, — a state in its duration; as Jno. xv. 27 ἀπ’ ἀρχῆς μετ’ ἐμοῦ ἐστέ, viii. 58 πρὶν ᾿Αβραὰμ γενέσθαι ἐγὼ εἰμί.” (Georg Benedikt Winer, A Grammar of the Idiom of the New Testament (Andover: Warren F. Draper 1897), p. 267.)
Many other commentators have made the same observation as Winer, see Archibald T. Robertson, A Grammar of the Greek New Testament in the Light of Historical Research Nashville Tennessee: Broadman Press, 1934, p. 394; McKay, Kenneth L. McKay, A New Syntax of the Verb in New Testament Greek: An Aspectual Approach New York: Peter Lang Publishing, Inc., 1994, p. 42; Sanders, Joseph N. Sanders, A Commentary on the Gospel According to St. John, Edited and Completed by B.A. Mastin London: A. & C. Black, 1968, p. 158. and Moulton. James H. Moulton, A Grammar of the New Testament Greek London, New York: T & T Clark International, 1960, p. 62.
While the verb εἰμί is in the present tense, the reference is to a past-tense setting, namely "before Abraham," therefore in this place, the present tense verb “indicates the continuance of an action during the past and up to the moment of speaking.” (Ibid.) The language used in St. Joh. 8:58 is an especially emphatic claim of pre-existence, where Christ claims to have existed continuously before the time of Abraham down to when he spoke these words, Loader concluded his discussion of the narrative this way,
“The conflict reaches its climax when Jesus asserts his pre-existence: ‘Before Abraham came into being, I am’ (8:58). Again, the precise meaning of ‘I am’ will depend on factors outside the immediate passage. The attempted stoning (8:59) might suggest blasphemous utterance of the divine name, but need not either here or elsewhere. Need it mean more than the stupendous claim: ‘I am in existence since before Abraham?’” (William Loader, The Christology of the Fourth Gospel: Structure and Issues (Berlin, Bern, New York, Paris, Wien: Peter Lang, 1992), p. 48.)
This seemingly wild claim to pre-existence would have merited the Jews hostile response, but would it have merited stoning? Why should a claim of pre-existence merit stoning? Appropriating the divine name as well would explain this.