I tend to agree with commentators who view verse 15 as a secondary addition to the Prologue hymn. It interrupts the flow of verses 14, 16 (cf. below), and is rather awkward in context. For this reason, and because of the difficulties in explaining why it was inserted at this particular location in the hymn, I am holding off on a discussion of verse 15 until our study of the hymn, properly speaking, has been completed.
As a confirmation of the point made above, regarding the intrusiveness of v. 15, note how vv. 14 and 16 flow together (as a poetic unit, or strophe) when 15 is removed:
“And the Word came to be flesh
and put down (his) tent among us,
and we looked at his splendor,
splendor as an only (Son) alongside (the) Father,
full of (His) favor and truth—
and out of his fullness
we all (have) received,
and favor in place of favor.”
We will examine each of the phrases in verse 16, beginning with the first phrase:
o%ti e)k tou= plhrw/mato$ au)tou=
“(and it is) that out of his fullness”
There are four elements to this phrase that need to be examined in turn.
The conjunctive particle o%ti is problematic. This is evidenced by the manuscript tradition, which is divided between o%ti and the conjunction kai/ (“and”). The particle o%ti is the reading in many of the “oldest and best” manuscripts (Ë66 Ë75 B a C* D L 33 579), but kai/ has more widespread support. Admittedly, o%ti is the more difficult reading, and is perhaps to be preferred on that basis.
The presence of the intervening verse 15 complicates the situation, since o%ti may have been introduced, whether by the author/editor or a copyist, to facilitate the return to the hymn after v. 15. If we accept the theory that an existing hymn was adapted in the Prologue, then we have to ask whether o%ti was the reading in the original hymn. If so, then we must consider further the force of this particle in context.
One possibility is that it indicates purpose or result—that is, the Son was filled (by the Father) so that we (believers) would come to share in the same fullness. Another option is that the clause in verse 16 is epexegetical, introducing a new thought that supplements or explains the prior line(s). The sense would then be: the Son was filled (by the Father), and now it is that we (as believers) also receive from this fullness. I have generally adopted the latter option, translating o%ti with the sense of “(and it is) that”. From the standpoint of the poetry of the hymn, however, I have shortened this to “and”, which is equivalent to the simple conjunction kai/. Copyists may have made a similar substitution, to clarify the line.
The preposition e)k (lit. “out of”) is an important element of the Johannine vocabulary, in two respects: (a) it refers to the source or origin of the Son (Jesus), and reflects the true origin of believers as well—being from God; and (b) it draws upon the birth language and imagery that runs through the Johannine writings, referring to Jesus as the Son and believers as the children (“offspring”) of God. The connection between believers and God the Father is established through Jesus the Son. He is the intermediary, and the divine/eternal Life we experience comes through (or “out of”) him. Ultimately, this is realized through the Spirit that proceeds out of Jesus and into us (7:37-39; 20:22, etc). There is a concrete illustration of this in the Johannine Passion narrative, when the “blood and water” comes out of Jesus’ side (19:34); on the association of the Spirit with this “blood and water”, cf. the allusion in 19:30, and especially the discussion in 1 John 5:6-8.
The noun plh/rwma (“fullness”) occurs only here in the Johannine writings. It is relatively rare in the New Testament as a whole (17 times), occurring most frequently in the Pauline letters—cf. Gal 4:4; Rom 11:12, 25; 13:10; 15:29; and 1 Cor 10:26 (citing Ps 24:1). However, the only real theological use of the word, comparable to the context here in the Prologue-hymn, is found in Colossians and Ephesians. Most notably, it is used in the Colossians Christ-hymn, at 1:19 (with an expository parallel in 2:9):
“…He [i.e. God] considered (it) good (for) all the fullness [plh/rwma] to put down house [i.e. dwell] in him” (1:19)
“…all the fullness [plh/rwma] of the Deity put down house [i.e. dwelt] in him” (2:9)
Clearly, in the context of this Christ-hymn, plh/rwma refers to the fullness of God. Everything that characterizes God, and that distinguishes him from created beings, is present in the Son. Ephesians 1:23 makes much the same point regarding the person of Jesus, but with greater emphasis on believers as the body of Christ. The implication is that, much like in v. 16 of the Prologue-hymn, believers share in the fullness of Christ (cp. Eph 3:19; 4:13).
In v. 16, the “fullness” (plh/rwma) is defined in terms of God the Father filling the Son (adj. plh/rh$). Specifically, he is filled with the “favor” (xa/ri$) and “truth” (a)lh/qeia) of God (v. 14). As I noted, from the standpoint of Johannine theology, that pair of terms essentially refers to the Spirit of God. The Son is filled with the Spirit (cf. 3:34-35), even as Jesus, during his earthly ministry, is said to be “full of the Spirit” (Lk 4:1, see also vv. 14, 18, and the context of the Baptism [3:22]). And we, as believers united with Jesus, share in the fullness of his Spirit.
The final word in the phrase is the genitive pronoun au)tou= (“of him, his”). This emphasizes that the fullness belongs to the Son—it is his, and he truly possesses it. That which is of God (the Father) belongs to Jesus (the Son). At several points in the Gospel, the point is made that the Father gives “all things” to the Son, so that, as the Son, he possesses everything that belongs to the Father (3:35; 5:20, 22; 6:37-39; 16:15; 17:7, 10).