Soulen’s chapter can be summarized in his own words:

Barth challenged Christians to speak of the mystery of eternal generation in every available way. I have proposed that in practice this means cultivating three patterns of scriptural speech: one that emphasizes the First Person and the mystery of divine uniqueness at the source of the triune life; one that emphasizes the Second Person and the mystery of divine copresence at the heart of the Trinity; and one that emphasizes the Third Person and the mystery of connection mutual blessing that glorifies the Trinity in eternity and time. My hope is that by cultivating these three forms of speech Christians might speak of the mystery of eternal generation—not adequately, but perhaps a little less inadequately. (146)

Irons begins by asserting that eternal generation of the Son and eternal procession of the Spirit are “an  essential component of Trinitarian orthodoxy” since they provide for personal distinctions that do not undermine the unity or simplicity of the Trinity. He then raises the problem of modern exegetes interpreting differently the texts that the church fathers saw as grounding the doctrine. Irons wishes to address this problem by arguing that monogenēs as used in John’s writings of Christ supports the doctrine of eternal generation.

Irons first notes the high frequency of monogenēs in the Greek fathers. He also claims that Latin translations of this term favor the understanding of “only begotten.” Tyndale translated monogenēs as “only begotten” in John 1:14, 18; 1 John 4:9 and as “only” in John 3:16, 18. The KJV translated “only begotten” in all of these verses. The shift away from the translation “only begotten” to “only” began with an 1886 commentary by B. F. Westcott. (Irons notes that Hort authored an essay defending the sense “only begotten.”) A 1938 Southern Seminary dissertation expanded on Westcott’s argument, and the translation “only” was adopted in the RSV. Dale Moody wrote an influential 1953 article defending this decision. After this point the NIV also adopted the translation “only,” and Richard Longenecker defended the translation. Since then the CEV, ESV, HCSB/CSB, NAB, NLT, NRSV, RSV have also followed this line.

Irons rebuts the claim of Westcott, Moody, et al. that monogenēs was interpreted as “only begotten” due to the Arian controversy. He quotes Justin Martyr, Dialogue with Trypho 105, “I have already proved that He was the only-begotten of the Father of all things (μονογενὴς γὰρ ὅτι ἦν τῷ πατρὶ τῶν ὅλων οὗτος), being begotten (γεγεννημένος) in a peculiar manner Word and Power by Him, and having afterwards become man through the Virgin” (102). Here monogenēs is interpreted by γεννάω/”being begotten.” Tertullian also used the Latin equivalent of monogenēs, unigentius, in a way that clearly means “only begotten” (Against Praxeas 7, 15).

Those who claim that monogenēs means only or unique Son argue that “monogenēs is derived from μόνος + γένος (“kind”), understood as deriving from γί(γ)νομαι (“be, become”) rather than γεννάω (“beget”), with the result that it means “only one of its/his kind”” (103). Irons responds: 1.  γί(γ)νομαι and γεννάω are from the same root and both can refer to birth. 2. Many Greek words contain the -genēs stem: “Examples include θαλασσογενής (“sea-born”), κογχογενής (“born from a shell,” picture the Birth of Venus by Botticelli), μοιραγενής (“favored by destiny at birth, child of destiny”), νεογενής (“new-born, newly produced”), πατρογενής (“begotten of the father”), προτερηγενής (“born sooner, older”), and πυριγενής (“born in or from fire”). Fewer than 12 of the 145 –genēs words involve meanings related to “kind” (e.g., ὁμογενής means “of the same genus”), and there are a few with miscellaneous meanings (e.g., διγενής, “of doubtful sex”)” (104). 3. There are Greek names that contain -genēs and they tend to indicate the idea of birth (e.g., “Hermogenēs (“offspring of Hermes”).”

Irons clarifies that he is not claiming that monogenēs never means “unique” or “one and only” and always means “only begotten.”

Irons then turns to survey usage (noting that the etymological argument was given to remove objections; he will substantiate his thesis based on usage). He claims that the “earliest meaning” of the term is “in reference to an only child” (105). He cites Hesiod’s reference to son without siblings with whom he would need to divide the inheritance with.

The word is used most frequently as an adjective modifying the nouns “son,” “daughter,” and “child.” This can be seen in the ordinary, non-Johannine, non-Christological uses in the New Testament (Luke 7:12; 8:42; 9:38).30 If the word meant “only,” then we would expect to find it used to modify many other nouns that do not involve the concept of being begotten or being an offspring, for example, “only wife,” “only brother,” “only friend,” “only slave”; or “only eye,” “only foot,” “only hand”   p 107  (for a person missing one eye, foot, or hand); or a man’s “only garment,” “only house,” “only sword,” and so on. But such collocations are completely absent in extrabiblical Greek. This suggests that the literal meaning, which is by far the most common usage in extrabiblical Greek, is the straightforward biological meaning: “only begotten,” that is, “without siblings” (106-7).

Irons notes that the “basic meaning” “only begotten” is extended metaphorically. But this extended meaning is extending from the basic biological sense (107-8). Thus μονογενης can be used of Isaac even through Ishmael preceded him because Isaac was the only heir of Abraham (108). He finds a similar usage in Agamemnon (109). This is how Irons understands Hebrews 11:17 (109).

A second metaphorical extension occurs when something is metaphorically “only begotten,” as in the universe of God (Plato) or wisdom as God’s “only begotten” (Wisdom of Solomon 7:22; cf. prov. 8:25) (110).

The third metaphorical sense is “only one of its kind,” which Irons says is found primarily, though not exclusively, in scientific literature (111). Irons observes, “The scientific meaning, ‘only one of his kind,’ is the meaning that modern scholars and English versions attempt to find in the five Johannine passages. But the five Johannine passages clearly do not fit under the third nonliteral extension. The genre and context are not scientific. The Gospel of John is dealing with the relationship between the Father and the Son, not botany. We are not dealing, like Theophrastus, with genus/species analysis. The father-son analogy is very strongly attested in these contexts, as opposed to the scientific usage, where this analogy has dropped from view” (112).

Irons then turns to John 1:14, 18. His conclusion regarding John1:14: “It is difficult to see how the meaning “only” or “one and only” fits in a meaningful way unless the notion of sonship or begottenness is part of the meaning of the word. Indeed, many of the modern English versions (like the Old Latin—see note 4 above) bring back the supposedly banished concept of begetting by adding the word “Son”  even though it is not present in Greek: “And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth” (ESV), and “the glory of the one and only Son, who came from the Father” (NIV). Both these English versions, though refusing to see “begetting” as part of the meaning of monogenēs, nevertheless cannot avoid inserting the word “Son,” even though it is not present in Greek. In like manner, C. H. Dodd—though taking monogenēs as “only of his kind”—recognized that “one who is μονογενής relative to a πατήρ can be no other than the only son.” The context is pushing the translators and the commentators in the right direction, almost against their will (112-13).

In John 1:18, Irons holds that “only begotten” is the best sense whether the reading ὁ μονογενὴς υἱός or μονογενὴς θεός is adopted (113). He notes, “The NIV renders monogenēs as “the one and only Son” and takes theos in apposition to it, “who is himself God.” Again, as we saw in verse 14, the context is pushing the translators to recognize that the concept of sonship is present in the pregnant word monogenēs (114). However, he objects to the ESV’s rendering, “the only God,” “First, perhaps without fully realizing it, the ESV translators have removed this one occurrence of monogenēs out of the frame of reference of the other four Johannine occurrences, in all of which monogenēs is used in reference to the uniqueness of the person of the Son: “the only Son from the Father” (John 1:14 ESV), “his only Son” (John 3:16; 1 John 4:9 ESV), or “the only Son of God” (John 3:18 ESV). On the ESV’s rendering of John 1:18 (“the only God”), the adjective “only” is an attributive modifying God (generic deity) rather than the Son” (114). Irons also thinks that the ESV could be misread as teaching “modalistic monarchianism or the “Jesus only” heresy” (114) and as excluding the Father from “the only God” (114).

Irons concludes that these texts do, in fact, teach the Son is eternally begotten of the Father: “John views Christ as the only begotten Son of God in the sense that he is the Father’s only proper offspring deriving his divine being from the Father. The fact that John 1:18 adds that he “is” (ὤν, present participle) in the bosom of the Father (ὁ ὢν εἰς τὸν κόλπον τοῦ πατρός) underscores that his sonship transcends time and is not to be interpreted as a temporal event like ordinary human begetting. The phrase εἰς τὸν κόλπον reinforces this by emphasizing the profound intimacy and love between the Father and his only begotten Son. We may conclude that, for John, the Son is eternally generated by or begotten of the Father” (115).

Irons also clarifies what eternal begetting doesn’t and does mean: “like all metaphors, there are notable points of discontinuity: unlike a human begetting, this begetting (1) had no beginning, (2) did not occur in time, (3) does not grant the Father chronological priority over the Son, and (4) lacks the involvement of a mother. But there is an analogy between human biological begetting and intra-Trinitarian begetting. The main points of continuity are: (1) the Father is the source or cause of the Son, (2) the Son possesses the same nature (homoousios) with the Father who begat him, (3) the Father delights in his Son and calls him “beloved,” and (4) it is fitting that the Son is the one sent on a mission from the Father to do the Father’s will” (116).

Finally, Irons concludes by noting that the doctrine of eternal generation rests on a broader foundation than the lexical meaning of monogenēs.

Like others, I found Iron’s argument convincing, and it led me to revise the understanding of monogenēs that I came to in seminary (though, I must confess that our systematic theology professor was skeptical of the modern consensus view, and that I came to my position via Reymond and Grudem).

Carson begins by surveying three common interpretations of John 5:26 among modern interpreters, including the traditional interpretation that connects this passage to eternal generation. Carson argues in favor of the traditional interpretation. He notes that in context Jesus was claiming to be God in such a way that he is not a “second” God alongside the True God. And yet the Son distinguishes himself from the Father. He does only what he sees the Father doing. But this claim to do what the Father does is a claim to be God—because he is doing all that God does. So when John 5:26 says that just as the Father has life in himself, so also the Father has given the Son life in himself, the context would affirm that this this is the self-existent life of God and that in some way the Father granted it to the Son. This does point to the doctrine of eternal generation of the Son.

Carson also reflects briefly on Lee Irons’s works on μονογενης (since the usage of that term in John forms the broader context for this text). Carson explains that Irons’s work has convinced him to change his position. However, he issues the following helpful caveats. Irons demonstrates “only begotten” as one meaning, but not as the only meaning of the term.  The sense “‘only’ seems to be a perfectly adequate understanding” in Luke 7:12; 8:42; and 9:38. Second, the sense “only begotten” does not itself require eternal generation. The lexical argument that Irons makes is only a component of a much larger argument. Third, Carson dissents from Irons’s interpretation of Hebrews 11:17. He holds that “unique son” is the best understanding of that text. I would agree with Carson on these points.

Carson concludes by briefly surveying other potential eternal generation texts. He finds Hebrews 1:3 to be a compelling text, but he argues that Psalm 2:7 refers to the Messianic kingship of Christ rather than to eternal begetting.

In conclusion, Carson argues for a taxis or ordering between Father, Son, and Spirit while acknowledging that the terminology of subordination at the very least carries problematic connotations.