Καὶ ὁ λόγος σὰρξ ἐγένετο καὶ ἐσκήνωσεν ἐν ἡμῖν, καὶ ἐθεασάμεθα τὴν δόξαν αὐτοῦ, δόξαν ὡς μονογενοῦς παρὰ πατρός, πλήρης χάριτος καὶ ἀληθείας.
Note the verb ending. It is clearly a middle/passive ending.
δόξαν ὡς μονογενοῦς παρὰ πατρός
δόξαν here is in apposition to the previous δόξαν.
ὡς is used to make comparisons (GGBB 761–762).
μονογενους is a substantival adjective.
πατρός is a third declension noun; here it is genitive singular and the OP of παρὰ.
πλήρης χάριτος καὶ ἀληθείας.
πληρης is an adjective meaning “full”. ?
It is a good idea to learn how to use MBG. Here’s how:
- First, you need to find the lexical form of the word you are analyzing. The lexical form of χάριτος is χαρις. MBG gives n3c(1) as the code for this noun (see the index in the back). If you go to MBG p. 194, you’ll see the paradigm. This will help you parse it. Compare this with the case endings.
- The lexical form of ἀληθείας is αληθεια. MBG gives its code as n-1a. You’ll find the information for these nouns on page 168 of MBG.
Ἰωάννης μαρτυρεῖ περὶ αὐτοῦ καὶ κέκραγεν λέγων·
οὗτος ἦν ὃν εἰπον·
Since there is no noun for ουτος to modify, you’ll have to supply one (BBG 13.7).
ἦν is from ειμι.
The relative pronoun ον is accusative case. Hence, it must be the object of ειπον. “This One was; I said [about] Him…”
- Notice that the gender and number of ον agree with ουτος since that is what it modifies (BBG 14.9).
- Notice that that case of ον reflects the fact that it is the the object of ειπον. (BBG 14.10)
ὁ ὀπίσω μου ἐρχόμενος ἔμπροσθεν μου γέγονεν,
Understand the difference between direct and indirect discourse.
ὁ ὀπίσω μου ἐρχόμενος
ερχομενος is articular. The article before οπισω belongs with ερχομενος. ὁ ὀπίσω μου ἐρχόμενος
Since it is articular, it must be adjectival; and hence, either attributive or substantival. Here it is substantival, “the One Who comes…” Since it is substantival, it must be functioning as a noun. Here it is the subject of γεγονεν.
οπισω μου is modifying ερχομενος.
ὅτι πρῶτος μου ἦν.
Another dependent clause. οτι can actually be either a subordinating conjunction or a relative pronoun. Sometimes, it means “because…” (a subordinating conjunction). Other times, it means “that…” (a relative pronoun). Only the context can decide. Here, it is likely a subordinating conjunction. Hence, the dependent clause is adverbial and modifies γεγονεν.
Consult RWP for the difference in meaning between ἔμπροσθεν μου and πρῶτος μου.